The biogeographical position of the Tristan da Cunha archipelago based on floristic records.

Abstract

The archipelago Tristan da Cunha is situated in the South Atlantic Ocean, about midway between South America and southern tip of Africa. It represents one of the least disturbed temperate island systems in the world, supports many endemic plant and animal species. Although the locality is interesting by many aspects, many fields still remain under-studied. This bachelor thesis presents a synthesis of available literature about the archipelagos non-marine non-vascular floras, which are of a great diversity, but mostly still overlooked by scientist. For some of them were made lists of taxa present. Further, the distributional ability and patterns of this plant groups are discussed.
KEYWORDS: Tristan da Cunha; Oceanic islands; Botanic; Distribution; Island Biogeography; Lichens; Mosses; Liverworts and Hornworts; Diatoms;

Full text

Univerzita Karlova v Praze
Přírodovědecká fakulta
Studijní program: Biologie
Studijní obor: Ekologická a evoluční biologie
PETRA VINŠOVÁ
The biogeographical position of the Tristan da Cunha archipelago based on floristic records.
Biogeografická pozice souostroví Tristan da Cunha z pohledu floristických studií.
BAKALÁŘSKÁ PRÁCE
Školitel: Mgr. Kateřina Kopalová, Ph.D.
Praha, 2014

Prohlašuji, že jsem závěrečnou práci zpracovala samostatně a že jsem uvedla všechny použité informační
zdroje a literaturu. Tato práce ani její podstatná část nebyla předložena k získání jiného nebo stejného
akademického titulu.
V Praze, 13.5.2014 Podpis

ACKNOWLEDGEMENTS
First of all, I would like to thank my family for supporting me during my studies and during the work
on bachelor thesis.
Furthermore, I would like to thank my supervisor Kateřina Kopalová, for her help with literature
search, help with writing my thesis and also for showing me an interesting world of diatoms and the many
opportunities students have nowadays. My gratitude also belongs to Bart Van de Vijver, who was like an
external supervisor for me, for his help with searching for old literature, invaluable insight about the topic
and also for correcting my texts.
Many thanks also go to my friends and to my boyfriend, for their tolerance and moral support.

ABSTRAKT
Souostroví Tristan da Cunha je jedním z nejméně porušených temperátních ostrovů světa, s mnoha
druhy endemické flory a fauny, nacházející se v Jižním Atlantickém oceánu, přibližně uprostřed mezi Jižní
Amerikou a nejjižnějším výběžkem Jižní Afriky. Ačkoliv se jedná o tak zajímavou lokalitu, v mnoha směrech
zůstává stále neprobádanou. Bakalářská práce představuje souhrn veškeré dostupné literatury o
bezcévných rostlinách vyskytujících se na zmíněném souostroví. Jedná se o značně diversifikované
skupiny, přesto vědci mnohdy přehlížené. V rámci bakalářské práce je vytvořen list jednotlivých zástupců.
Nakonec je diskutována schopnost bezcévných rostlin se šířit na dlouhé vzdálenosti, jakožto i charakter
jejich rozšíření.
KLÍČOVÁ SLOVA: Tristan da Cunha; oceánské ostrovy; botanika; distribuce; ostrovní biogeografie;
lišejníky; mechy; játrovky; hlevíky; rozsivky;
ABSTRACT
The archipelago Tristan da Cunha is situated in the South Atlantic Ocean, about midway between
South America and southern tip of Africa. It represents one of the least disturbed temperate island
systems in the world, supports many endemic plant and animal species. Although the locality is
interesting by many aspects, many fields still remain under-studied. This bachelor thesis presents a
synthesis of available literature about the archipelagos non-marine non-vascular floras, which are of a
great diversity, but mostly still overlooked by scientist. For some of them were made lists of taxa present.
Further, the distributional ability and patterns of this plant groups are discussed.
KEYWORDS: Tristan da Cunha; Oceanic islands; Botanic; Distribution; Island Biogeography; Lichens;
Mosses; Liverworts and Hornworts; Diatoms;

CONTENTS
1 INTRODUCTION ............................................................................................................................................ 1
Island biogeography ......................................................................................................................... 2
History highlights ............................................................................................................................. 5
Objectives and importance of the study .......................................................................................... 7
2 TRISTAN DA CUNHA ARCHIPELAGO ............................................................................................................ 8
Geology: origin and structure .......................................................................................................... 8
Climate ............................................................................................................................................. 9
Habitat types .................................................................................................................................. 10
3 FLORISTIC RECORDS ................................................................................................................................... 13
Lichens ............................................................................................................................................ 13
Bryophytes ..................................................................................................................................... 15
Mosses (Musci) .................................................................................................................. 15
Livervorts (Hepaticae) and Hornworts (Anthocerotae) ..................................................... 18
Algae .............................................................................................................................................. 19
Diatoms (Bacillariophyta).................................................................................................. 20
4 DISCUSSION ............................................................................................................................................... 22
Lichens ............................................................................................................................................ 22
Mosses ........................................................................................................................................... 23
Liverworts and Hornworts .............................................................................................................. 24
Diatoms .......................................................................................................................................... 25
5 CONCLUSION .............................................................................................................................................. 27
6 REFERENCES ............................................................................................................................................... 28
7 APPENDICES ............................................................................................................................................... 33

1
1 INTRODUCTION
From the very beginning scientists from all over the world were fascinated by the unique nature
of remote oceanic islands, especially since Charles Darwin’s work on the Galapagos Islands. These young
oceanic islands of volcanic origin are summits of large volcanoes that rose from the bottom of the
oceans. They are isolated from other lands by many miles of deep sea and have never been connected
to continental landmasses. Their environment is truly unique as everything is fundamentally a product
of trans-oceanic dispersal (Wace & Holdgate 1976; Cowie & Holland 2006) and eventually subsequent
speciation. Generally, the oceanic islands lack indigenous land mammals and amphibians, but typically
have many of birds and insects, and occasionally also some reptiles. They provide us with a suite of
natural laboratories, from which the discerning natural scientist can make a selection that simplifies the
complexity of the natural world (Whittaker & Fernandez-Palacios 2007).
The Tristan da Cunha group along with Gough Island are not only known because of their
remoteness, but also because of the limited human impact, as 44% of the group’s land area has been set
aside as permanent nature reserve, making it one of the least disturbed temperate island systems in the
world (Ryan et al. 2007). Wace (1965) reported that although the Tristan da Cunha archipelago is a
remote one, its biota is significantly diverse ecologically with a substantial native flora and fauna in
which the pre-human ecological status quo is still largely preserved. Two of four island, Gough and
Inaccessible Island, were inscribed as UNESCO World Heritage Sites in 1995 (under criteria vii, x) but
there is still only a limited awareness of the global importance of this area, the rich species diversity they
contain and of the threats they face (Ryan et al. 2007). The island group supports many endemic
species, some of which are globally threatened with extinction.
A constant threat for an island’s biota is the introduction of non-native species. Alien plant species
can be found on all islands of the archipelago, especially on the main island Tristan da Cunha (or
‘Tristan’), which is also the most remote inhabited island on the world, with a permanent population of
some 270 people who lives in the settlement Edinburgh of the Seven Seas. The three outer islands
(Inaccessible, Nightingale and Gough) remain in a largely undisturbed state, despite the presence of a
number of introduced species. They are, however, constantly at risk of introduction of new species as a
result of visits by tourists, scientists and Tristan islanders (Gremmen & Halbertsma 2009).

2
ISLAND BIOGEOGRAPHY
Biogeography deals with distribution of species through geological time and in geographical space.
Many gradients are involved (e.g., latitude, area, soil, age, isolation etc.) resulting in biogeography as a
multidisciplinary domain of many different areas of science – such as evolution, geology, taxonomy,
ecology, climatology and palaeontology (Cox & Moore 2010). The tasks of biogeography are briefly,
which species, where and why (or why not?) as was clearly stated by Quammen (1996). However, Island
biogeography has its own arrangements which have to be stated.
The geographic locality of the Tristan da Cunha archipelago is clearly specific by its remoteness
and its isolation. Before the actual human influence to the environment, all terrestrial animals and
plants have had to disperse over long distance from the source. Thus, the biogeography and biodiversity
of the archipelago are fundamentally products of trans-oceanic dispersal from elsewhere, subsequently
enriched by speciation resulting in endemic biodiversity. This is clear for the islands which have never
been connected to a continental landmass (Cowie & Holland 2006). Since plants are not capable of
locomotion, seeds and spores can disperse only passively by wind (anemochory) or by flotation in the
sea (thalassochory), they also can ‘hitchhike’ on some birds and disperse attached to feathers
(exozoochory), legs, or even by the digestive system (endozoochory); birds then use oceanic islands as
stepping stones during their migration but will eventually leave behind some species (MacArthur &
Wilson 1967; Whittaker & Fernandez-Palacios 2007). Furthermore, the large distance across the ocean
defines the species composition found on the islands. Some taxa have inherently worse dispersal
abilities thus are unable to colonize more geographically isolated islands. Above that, also some
direction of dispersal is often more dominant than the other – like predominant east-west winds ‘West
Wind Drift’ around Antarctica in the case of the Tristan da Cunha archipelago (see Fig. 1.1) and other
landmasses in the Southern Hemisphere. The wind connectivity among southern islands is clearly a force
driving current plant distribution, as for example Muñoz et al. (2004) found a stronger association to
floristic similarities of mosses, liverworts and lichens, with maximum wind connectivity than to
geographical proximity (using Mantel tests). He also stated that dispersal events are rather episodic than
gradual. Nevertheless, the common migratory routes of birds are typically north-south oriented and less
in other directions (Gillespie et al. 2012); birds can also provide a distribution of plant species among the
southern islands. However, it’s obvious that many species not-adapted to long-distance dispersal would
never get there unless with the human help. This results in a highly disharmonic biotic composition on
the remote islands lacking many of worldwide common species and also major elements of the biota of
continents. Moreover, native species often lack defenses against grazing or predation (Vitousek 1988;
Cowie & Holland 2006; Whittaker & Fernandez-Palacios 2007).

3
Figure 1.1 Floristic affinities of Gough Island in relation to the predominant wind direction as revealed by the flight of a balloon:
areas sharing 20-25 species, cross hatch; 15-20 species, single hatching; 10-15 species, heavy stiple; 5-10 species, light stipple.
(Whittaker & Fernandez-Palacios 2007 after Moore 1979) The affinities with New Zealand and South America are clearly visible.
Also the relationship between the number of species and an island area is well documented.
More species occur on bigger islands than on the smaller ones, precisely because of the number of
habitats (Townsend et al. 2009). This was well presented in the classic monograph by MacArthur &
Wilson (1967): The theory of island biogeography, in which the species-area relationship was clearly
specified. The relationship was firstly established for animal species example, but was also extended for
botanical species, ending up with similar results. According to them, the number of species on an island
is usually approximately related to the area of the island by equation S = cAZ , where S is the number of
species, A is the size of the area, c is a constant which varies widely among taxa and according to the
unit of area measurement (which thus vary from system to system), and z is a constant which is, in most
cases, varying between 0.20 and 0.35 (for more details, see MacArthur & Wilson (1967) Chapter 2).
Other idea is that the more isolated an island is, the lower is the species number (Cox & Moore
2010). Unfortunately, with increasing isolation, other properties adherently also vary, such as the area
of islands, although the distance effect has been hard to test (Whittaker & Fernandez-Palacios 2007).
This phenomenon can be explained by the fact that immigration and evolutional processes together are
not able to achieve a species equilibrium, compared to rates of immigration to islands near major
sources (Schoener 2009). This explanation is supported by several recent findings of successful insular
colonization by invasive plants. For example Sax et al. (2002) and Sax & Gaines (2008) have shown that
although the number of bird species currently found on remote oceanic islands (both native and

4
introduced) is not higher than the number that was there before human occupation, but the number of
plant species almost doubled at the same time, increasing in quantity significantly over last 200 years
(Fig. 1.4). These findings suggest that communities may be under-saturated for plants and could support
more in total. This also supports the findings of Wace & Dickson (1965) who pointed out that the native
biota are disharmonic lacking many species that can successfully invade the native communities not
affected by man’s activities (as could be seen on several alien therophytes). The dynamics of species
distribution on remote islands such as those of the Tristan da Cunha archipelago is therefore much more
complicated. Some turnover with endemic plant species becoming extinct and other new species
evolved or/and colonizing the island, can be often involved.
Figure 1.4 Naturalized plant richness has increased on oceanic islands in an approximately linear fashion over the past 200
years. The island does not show asymptote in cumulative richness of naturalized species over time. (Sax & Gaines 2008)
The equilibrium theory of MacArthur & Wilson (1967) (known as ETIB) says that the distribution
of species on islands can be interpreted as an equilibrium of opposite powers: extinction and
colonization. Species constantly get extinct and substituted through immigration by the same or
different ones. The ETIB process depends on the area of the island and its isolation, which, together,
drive the speed of immigration and extinction (Fig. 1.5).
Figure 1.5 The balance between immigration of new species and extinction of already established species on the
islands on near, far, small and large islands. Curves intersect at an equilibrium point of biotic diversity. (Cox & Moore (2010)
after MacArthur & Wilson (1963))

5
Beside immigration, other process is often involved, especially on remote isolated islands.
Evolution and therefore another possibility how to fulfill the remaining ecological space, comes into
question here. Speciation can serve as a surrogate for immigration on isolated islands and will
predominantly fulfill the open niches by adaptive radiation when enough time for the process is given.
The amount time is less an issue when the islands are remote, because the number of successful
colonizers is very low plus the associated abundance of open niches, provide them both time and
opportunity to adapt and often evolve to an unusual extent (Gillespie & Baldwin 2010). Both
colonization and evolutional processes are involved in adding new species to the community of an
archipelago; it’s a race between repeated colonization of pre-adapted species and single lineages that
evolve and expand their ecological range (Roughgarden 1972).
Evolution and speciation rates are higher than those of immigration; hence it results in a number
of endemic taxa found nowhere else on the world. Then although small in area, oceanic islands maintain
a disproportionately high biodiversity and number of endemic taxa than equal-sized areas elsewhere.
Consequently, it can be noticed that the isolation of separate biotic regions generally begets global
diversity (Cowie & Holland 2006; Vitousek & D’Antonio 1997). It is a paradox that immigration of alien
species decreases the diversity of an island flora – actually, it generally increases the total number of
species on an island but causes a globalization of species worldwide when driving out the native flora
(Lugo 1988; Vitousek 1988). Because of the endemism, it’s most welcome to preserve a minimum of
colonization events to oceanic islands and still conserve the unique species.
HISTORY HIGHLIGHTS
The very first contact of humans with the Tristan da Cunha archipelago is dated to the 16th century,
when there islands were discovered in May 1506 by the Portuguese (Wace & Holdgate 1976) and the
northern island was named after Admiral Tristao d’Acunha. Just a year before, in 1505, Gough Island
was discovered by Goncalo Alvarez, but later ‘re-discovered’ by Captain Gough of the British ship
Richmond in 1731 (Ryan et al. 2007).
However, the first recorded landing on Tristan da Cunha was not before 1643, followed by an
interest of sealing gangs in killing thousands of seals for oil and skins from about 1790 (Wace et al. 1966;
Ryan et al. 2007). In these times, poultry, goats and pigs were introduced and potatoes were cultivated
on the island, therefore some alien plants already become established in 1793 (Gremmen & Halbertsma
2009; Wace et al. 1966). However, recent results from the pollen analysis suggest that humans may
have visited Tristan da Cunha before the first recorded landing, as pollen of a non-native introduced
plant, Plantago lanceolata L. was found in one sample of a core from lowland peatland that was dated
to around 1570 (Ljung & Björck 2011). The beginnings of the Settlement on Tristan da Cunha date back
to the early 19th century, when it was established in 1815 with a self-supporting human population since
then. During the 19th century, Tristan da Cunha was an important provisioning station for many vessels

6
to the Pacific and Indian Oceans, although many visitors came or got by, not only those welcomed –
since also rats arrived from a shipwreck in 1882 and caused a massive destruction in native bird
populations and to crops. Humans of the Settlement had not only many potatoes plots but as recorded,
also other vegetable and fruit growing on the island between 1830 and 1870 – such as cabbages, onion,
turnips, carrots, strawberries, apples, pears and peaches. Anyway, by the end of 19th century, the
number of seals were so reduced that sealing was no longer profitable and the economy gradually
switched from trading to subsistence crofting. Many of islanders left Tristan Island and the population
fell by almost half to only 50 people and also, during the first half of 20th century, there was the largest
isolation as ships passed by only every one to two years (Wace & Holdgate 1976; Ryan et al. 2007). This
changed in the 1940s when a small naval garrison was stationed and also a crayfish caning factory was
built, which increased the contact with the outer world. In 1961, a volcanic eruption took place next to
the Settlement and everyone had to be evacuated from Tristan. The eruption caused great damage to
the vegetation, especially due to fumes that covered a wide area and also due to the grazing of suddenly
unwatched domestic animals, although some of them were also reduced by feral dogs (Wace &
Holdgate 1976; Gremmen & Halbertsma 2009; Ryan et al. 2007).
According to Wace & Holdgate (1976) the scientific interest began in 18th century. Great account
of persons, ships and expeditions who collected vascular plants can be found in Groves (1981). The first
big comprehensive scientific survey of the northern islands was done by the Norwegian Scientific
Expedition in 1937–38. Later on, on Gough Island, a first expedition was made by the Gough Island
Scientific Survey in 1956–57, which built up an expedition hut at The Glen on the east coast, later moved
and maintained as a South African Weather Station in 1963. The first proper exploration of Inaccessible
Island was done by the Denstone Exploration in 1982–83.
The lowland areas of Tristan da Cunha were exposed to substantial disturbances since the 17th
century as indicated by the erosion of the Settlement Plain (Ljung et al. 2006). Most of the original
lowland areas of Tristan have been transformed by intensive agricultural and grazing activity into
grassland dominated by alien plant species (Gremmen & Halbertsma 2009). Eventually, the first effort of
protecting the unique and greatly threatened environment of the Tristan da Cunha archipelago, took
place in 1976 when the Conservation Ordinance proclaimed Gough Island as a nature reserve and
provided some protection for seabirds and Island Trees at Tristan. As was mentioned before, also
Inaccessible Island was turned into a nature reserve and together with Gough Is., both islands form one
of only two British Natural World Heritage Sites in the UK Overseas Territories. Also half of the total
surface of Tristan da Cunha Island is protected. Furthermore, the community has adopted a Biodiversity
Action Plan (in 2006), controlling imported goods because of the threat of future accidental
introductions and also took its part in eradication programs for invasive alien species, as are New
Zealand Flax, Procumbent Pearlwort or rats and mice (Ryan et al. 2007).

7
OBJECTIVES AND IMPORTANCE OF THE STUDY
As we can see from recent paleoecology studies (Ljung 2007) the Tristan da Cunha archipelago had been
unaffected since its emergence to at least the late 16th century, and remained fairly untouched until the
first documented human landings in the 17th century. According to Ljung et al. (2006) the vegetation has
been rather stable for at least 2300 years, with no significant altitudinal shifts in the vegetation zones or
major changes in the species composition. Also pollen studies from Gough Island do not record any
major vegetation changes indicating that the island flora seems to be remained similar for at least
40,000 years (Bennett et al. 1989). This may indicate that the island biota had reached its own point of
succession, well before any human appearance. Truly, the environment of the islands belonged to no-
one but nature and can thus be considered a true product of natural laboratories.
The main aim of this bachelor thesis is to summarize all records known about non-marine non-
vascular flora that occur on the archipelago Tristan da Cunha. At present, such as summary does not
seem to exist on this topic. It can help future researchers working on ecology, climatology, biogeography
and distribution of micro-organisms in the Southern hemisphere. Together with background works done
predominantly on vascular plants (Wace & Holdgate 1958, 1976; Wace 1961; Wace & Dickson 1965;
Groves 1981; Ryan et al. 2007), this thesis can help to understand some biogeographical questions.
Due to its position, the archipelago has a great scientific potential as one of the most remote
places on the world. This can be advantaged for comparisons with other similar isolated islands such as
Ile Amsterdam and St. Paul in Indian Ocean. These two islands, although in a different ocean and
apparently some 7,400 km away, have similar climatic conditions as southern Gough Island and also are
already known for some floral and faunal similarities (Wace 1961). For example, the Gough-Amsterdam
connection involves Northern rockhoppers, Yellow-nosed albatrosses, some Sphagnum species (absent
from sub-Antarctica) and also the endemic Island tree, Phylica arborea (Van de Vijver, personal
communication). Following this thesis, future research targeting especially micro-organisms from Gough
Island may bring new information for this connection, as recent studies on Ile Amsterdam are already
being undertaken (Van de Vijver et al. 2008, 2012; Lowe et al. 2013; Van de Vijver & Cox 2013; Chattová
et al. 2011, 2014). Other biogeographical relationships can be studied based on floristic records – with
geographically neighbouring islands and landmasses (such as Saint Helena, southern Africa, Bouvet
Island, South Georgia, Marion and Prince Edward Islands) or based on dispersal wind highway from the
East (New Zealand, Tierra del Fuego, South America etc.) to the West (Ile Amsterdam, St. Paul Island
etc.).

8
2 TRISTAN DA CUNHA ARCHIPELAGO
The Tristan da Cunha archipelago, governed by the United Kingdom, is a dependency of the British
overseas territory of Saint Helena, Ascension and Tristan da Cunha. The archipelago, located in the
South Atlantic Ocean, is composed of four major islands and a large number of smaller islets. The first
three, Tristan da Cunha, Inaccessible and Nightingale (37 °S/12 °W) are only separated by narrow sea
straits of less than 20-40 km and are commonly referred to as the ‘Tristan Group’, named after the main
island of the archipelago, Tristan da Cunha. The fourth island, Gough Island, located more than 350 km
south-southeast of the Tristan Group (40 °S/10 °W), is the only other landmass within 2,000 km of the
Tristan Group (Wace & Holdgate 1958). Other closely located landmasses include for instance Saint
Helena Island at 2,430 km away to the North. For better understanding of its locality, see Figure 2.1.
Figure 2.1 Locality map of the Tristan da Cunha archipelago in the South Atlantic. After Hänel (2008).
GEOLOGY: ORIGIN AND STRUCTURE
The archipelago is one of the most remote places in the world, 2,800 km away from Cape Town, over
than 3,250 km from South America and approximately 3,430 km from the Antarctic Continent. The
islands are entirely oceanic, formed after a series of volcanic events, which means that they represent
the exposed parts of large volcanos and have never been connected to any continent or larger
landmass. The islands are positioned slightly east of the mid-Atlantic Ridge near its junction with the
aseismic Walvis lateral ridge, and rise from a water depth of about 3,500 m (Wace & Holdgate 1976).
Nevertheless, the sea straits between Nightingale and Inaccessible Isl. never exceed more than 500 m of
depth and they are separated from Tristan da Cunha, situated on different volcanic plinth, is it less,
some 2,000 m (Ryan et al. 2007).
The islands, although all of volcanic origin, differ in age. It’s remarkable and not so obvious for an
archipelago lying so closely together, compared to for instance the Galapagos Islands or the Hawai’i
archipelago. Although they had some periods of volcanism and still are not volcanically entirely extinct,
the age of every island is noticeable by the erosional stage, size and structure. The oldest one is

9
Nightingale, with rocks on one of its islet, Middle Island, being more than 18 million years old. The
island, the smallest of the archipelago (4 km2) is highly eroded, with two neighboring islets, Stoltenhoff
and Middle (or Alex) Island, and many low cliffs and sea caves. The island culminates at High Ridge, with
an altitude of ca. 400 m. Inaccessible Island is much younger (3 - 4 million years old), is medium-sized
(14 km2) culminating at 600 m (Swale’s Fell). It’s mostly eroded from the western side, where are the
highest cliffs of the island, from them the remaining surface then slowly sloping down to the east.
Tristan da Cunha, the only inhabited island of the archipelago with a population of less than 300 people,
is also the largest (96 km2) and the youngest one. The oldest rocks are only about 200,000 years old.
Furthermore, it is the last one that showed volcanic activity when it erupted in 1961 forming a new
volcanic cone just north-east of the Settlement (Edinburgh), covering an area of about 0,5 km2 in new
lava (Gremmen & Halbertsma 2009). The island itself has a typical volcanic shape, reaches 2067 m at its
highest point (The Peak) around which a gently sloping terrain called The Base can be found. It is
surrounded by steep precipices known as The Cliffs (Ljung et al. 2006) formed by marine erosion. Tristan
has also coastal lowlands – the settlement plain on north-west, where Edinburgh is located, and then
Caves-Stony Beach on the south side and the small Sandy Point on the eastern side. The last and most
isolated island is Gough Island with an age of about 3 - 5 million years (Ryan et al. 2007). It is actually the
tip of a large volcanic mass, completely separated from the Tristan group, with an erosional state
between Inaccessible Isl. and Tristan da Cunha (Miller 1964). The highest point, Edinburgh Peak, has an
altitude of ca. 910 m, surrounded by a plateau at 600 m a.s.l. with eight large and deep canyons known
as the ‘glens’ formed by fluvial erosion. Steep cliffs are found mainly on the western coast whereas the
plateau on the south slopes down more gently, although the area is very crossed by many small gullies,
including only an extensive area of land below the 300 m contour (Wace 1961). This is where the
Meteorological Station of South Africa is located inhabiting permanent 7 occupants. Gough itself has
also many small islets and rocks, such as Saddle Is. on the south, Tristani and Isolda Rock on the west,
Cone Is., Round Is., Church Rock and Loft’s Wife on the north and Pinguin Island more to the east with
The Admirals on the east side.
CLIMATE
The Tristan da Cunha archipelago has a strong oceanic influence, expressed by the typically wet and
often windy weather with a relatively stable annual temperature due to lagging effect of the
surrounding ocean. The islands are classified as a ‘cool temperate’ (Wace & Holdgate 1958; Wace &
Holdgate 1976; Preece et al. 1986; Ryan 2007) together with Ile Amsterdam and Ile Saint-Paul, both
located in the southern Indian Ocean (Clark & Dingwall 1985).
The Tristan Group is only about 250 km below the southern tip of Africa and can therefore have
relatively warm summers. The marine west coast climate is very typical lacking a dry season with an
annual temperature of 15,1 °C (range 2 to 25 °C) at sea level, decreasing with rising altitude. The mean

10
annual precipitation of Tristan da Cunha is 1,670 mm (Holmgren et al. 2011).
The Subtropical Convergence is situated sometimes between the Tristan Group and Gough Island,
sometimes more southward. It’s the boundary between the warm Subtropical surface waters coming
from the north and the cold sub-Antarctic surface waters from the South. Moreover, Gough is being
influenced by the upwelling of cool subsurface waters and its position is right on the edge of the so-
called ‘roaring forties’, making the weather on Gough rough, especially during the winter months. The
annual average precipitation of Gough is approximately 3,000 mm and it rains almost 300 days per year
with frequent gale-force winds (Elix et al. 2005). Gough Island’s average annual air temperature is
11,7 °C, varying between 8,9 °C in August and 14,5 °C in February (Jones et al. 2003) at sea level and the
annual precipitation averages the total for Transvaal Bay (site of the Weather Station) of 3,154 mm
(Turner & Pendlebury 2000).
According to Ryan (2007), the precipitation is up to 50 % higher on the peaks than at the coast.
This is mainly because the islands are mountainous (especially Tristan da Cunha and Gough) and
orographic clouds formed around the peaks induce an orographic rainfall from the cool moist air (Wace
& Holdgate 1976). The West Wind Drift affects the archipelago, with predominantly winds from the west
(36 km/h at Tristan and 44 km/h at Gough, with a tendency to be stronger during winter months (Ryan
et al. 2007)). The precipitation levels are the highest during the winter months when the west winds
move northward and bring more cyclones to the islands along with higher sea surface temperature
increasing the level of air humidity (Ljung & Björck 2007).
In the past, the island has not been glaciated (Chown et al. 1998). Pollen analyses from cores
suggest that the climate remained relatively constant during at least the last 20,000 years. According to
Bennett et al. (1989), the vegetation on Gough (and hence the climate) did not experience any major
changes in at least the past 40,000 years. However, the actual climate is influenced by Global Change, as
an increase in temperature has been noted since the 1950s and especially pronounced since late 1970s
(le Roux et al. 2013). It is generally known that warmer temperatures may improve the ability of alien
invasive species to settle, reproduce and successfully outcompete native biota which can lead to
significant biodiversity loss.
HABITAT TYPES
Terrestrial habitats found on the Tristan group and Gough Island, are defined by their dominating plant
communities. Natural vegetation zones tend to be subdivided by altitude, depending on their
exposition, generally at lower elevation at Gough Island than at the northern islands. A brief overview of
the habitats present on the archipelago can be found in this section, their composition and structure,
starting from sea level:

11
TUSSOCK GRASSLAND AND PASTURES: These grasslands are dominated by high (up to 3 m) and dense
tussock grass Spartina arundinacea (Thouars) Carmich, covering almost the entire surface of Nightingale
and its islets – Middle and Stoltenhoff, coastal lowlands and cliffs of Inaccessible up to 200-500 m. Once
this vegetation was dense at Tristan but is now replaced by pastures (Wace & Holdgate 1976; Ryan et al.
2010). Pastures can be found on Tristan at the base of the fringing coastal cliffs on the Settlement Plain,
The Caves, Stony Hill and Sandy Point. Spartina tussock cover is less developed at Gough, concentrated
to offshore stacks, cliffs and slopes. The smaller tussock grass Parodiochloa flabellate (Lam.) E.E. Hubb, is
forming a dense cover, especially along the western cliffs, but is excluded from areas that are naturally
disturbed therefore providing an opportunity to some plants such as Pig Dock (Rumex frutenscens
Thouars), and also to numerous introduced species to proliferate (Ryan et al. 2007; Wace 1961).
FERN BUSH: Dense fernbush communities of Phylica arborea Thouars, the Island Tree (5 to 8 m high,
sheltered places), joined by Bog Fern (to max. 2 m) Blechnum palmiforme (Thouars) C.Chr., are the two
main distinctive species that characterize the Fern Bush vegetation zone. This vegetation zone can be
found on all four islands, up to around 800 m at Tristan, on the wet peaty plateau of Inaccessible and on
the area around the Ponds at Nightingale, as well as on Gough up to 500 m, where it selects more
sheltered sites along the east-south coasts (Ryan et al. 2007; Wace & Holdgate 1976). Usually in upper
highs and on more exposed places, Bog Ferns heath communities grow, while Phylica woodland seems
to prefer more sheltered places and is excluded from areas above an altitude of 450 m. The trunks of
Blechnum and also Phylica wood lying on the ground are covered with a thick growth of Hymenophyllum
aeruginosum (Poir.) Carmich, whereas many bryophytes grow under the thick Phylica canopy and many
species of epiphytes can be seen on the branches, such as for example dense growths of Old Man’s
Beard lichen Usnea Dill. ex Adans., where a certain amount of orographic mist is frequently occurring.
Other plants are often found in a dense ground cover among trees, where they are more scattered –
Bog Ferns, Ctenitis aquiline (Thouars) Pic.Serm, Bracken Histiopteris incise (Thunb.) J.Sm., Elaphoglossum
laurifolium (Thouars) T. Moore and Asplenium obtusatum G.Forst., many flowering plants including Dog
Catcher Acaena sarmentosa Carmich., Berry Bush Empetrum rubrum Vahl ex Willd. and fowl berries
Nertera spp. Banks & Sol. ex Gaertn., in such places as is area between the Ponds on Nightingale, the
Small Bog Grass Scirpus bicolor Carmich. can be found (Wace 1961; Ryan et al. 2007).
WET HEATH: The Wet Heath vegetation zone includes many elements of other zones, making itself a
transitional vegetation type of plants only less than 0.5 m short, found approximately between 300 and
600 m, from the upper limit of Fern Bush. It consists of scattered dwarfed ferns B. palmiforme, B. penna-
marina (Poir.) Kuhn and Ctenitis aquilina, a large number of mosses, grasses, Scirpus and Carex sedges
and other flowering plants including Dog Catcher, fowl berries, Celery Apium australe Thouars,
Empetrum rubrum etc. This zone does not occur on lower Nightingale Island but is common on Gough

12
Island to above 800 m when sheltered. Also occur on small area on the highest western rim of the
plateau at Inaccessible Island, but is former to Tristan, now shifted to meadows dominated by two alien
species Holcus lanatus L. and Rumex acetosella L. (Wace 1961; Ryan et al. 2007; Wace & Holdgate 1976).
FELDMARK AND ALPINE HABITATS: At the higher elevations of Tristan and lower on Gough, where the
Wet Heath vegetation zone ends and soil is more exposed and windswept, only some plants can survive.
The diversity depends on soil stability and depth, which is diminishing with altitude. Empetrum
communities, Agrostis grasses and Scirpus sedges, Celery Apium australe, Tristan Cranberries Acaena
stangii Christoph. and the lycophytes (e.g., Lycopodium magellanicum Willd.), together with numerous
mosses and lichens, form the common vegetation of feldmarks; only few hardy lichens and mosses can
reach the montane scoria Tristan Peak (Wace 1961; Wace & Dickson 1965; Ryan et al. 2007).
BOGS AND OTHER WETLAND HABITATS: Bogs and wetlands are widespread at the islands, forming two
main types of bogs. At lower elevation they are dominated by floating mats of dense Big Bog Grass
Scirpus sulcatus Thouars. Typical examples of these are the Ponds at Nightingale and Skua Pond at
Inaccessible, with Scirpus bogs as well as with open patches of water, mud, and with Pig Dock and Carex
insularis Carmich. sedges on the edges. The other type consists of Sphagnum bogs, which typically occur
at higher elevations, locally on the plateau of Inaccessible and on the Base of Tristan (Soggy Plain,
at 740 m). More extensive bogs are found in the Gough Island uplands where wetter conditions and
suitable flatter topography prevail above 600 m. These peatbogs are dominated by Sphagnum mosses
(S. recurvum Beauv.), other bryophytes and a number of liverworts (e.g., Jamesoniella spp. (Spruce)
Lees), along with the only abundant plant Tetronicum magellanicum Willd. on Gough and also Scirpus
sedges, common in these bogs at the northern islands (Glass et al. 2006; Ryan et al. 2007; Wace &
Holdgate 1958; Wace & Dickson 1965; Wace 1961). Drainage bog streams are also present, and are
surrounded by mixed fen-like vegetations including Glyceria insularis C.E. Hubb. and C. insularis differing
from the Wet Heath community. Likewise Agrostis and Deschampsia grasses are abundant, as well as
introduced plants dispersed along streams, such as the widespread Rumex obtusifolius L. and the
aggressive alien Agrostis stolonifera L., both looking for disturbed openings after floods (Ryan et al.
2007; Wace 1961).
THE 1961 LAVA FIELD AND VOLCANO: The area is characterized by a young volcanic substratum, lacking
any soil formation and showing a very low water retention capacity. Only large black lava blocks or fine-
grained sandy deposit on the new volcano form the substratum (Gremmen & Halbertsma 2009).

13
3 FLORISTIC RECORDS
Although vascular plants dominate the terrestrial vegetation of the islands, it’s noteworthy to say that
this is reflected in the species richness which is much larger in non-vascular plants. Even Wace & Dickson
(1965) mentioned, although the species number recorded was significantly lower than nowadays, the
abnormally high proportion of mosses and hepatics compared to phanerogams on the archipelago,
based on Raunkiaer’s ‘quotients’ for bryophytes (Fig. 3.1).
no. of mosses x 11
no. of hepatics x 25
no. of phanerogams
no. of phanerogams
Tristan da Cunha archipelago
40
137
Juan Fernandez group
11
35
South Georgia
73
84
Faeroe Islands
10
12
Azores
2
3
Figure 3.1 An exceptionally high proportion of bryophytes to phanerogams, even for insular flora.
After Wace & Dickson (1965); data from Wace & Dickson (1965), Raunkiaer (1937) and Skottsberg (1956).
Although there is a higher number of species, the level of endemism is lower compared to
vascular plants. It’s due to the effective long-distance dispersal ability of spores which is even more
effective for vegetative propagules, via birds, ocean current and West Wind Drift (Galloway 1996;
Jørgensen 1977; Elix & Gremmen 2002). According to this, the distribution of species clearly shows some
phytogeographical affinities to some continental landmasses, as would be discussed below or in the
Discussion (from p. 22).
LICHENS
Lichens are widespread among the islands of the Tristan da Cunha archipelago. They grow on different
substrates, from the sea level up to the highest point of the Tristan Peak. Foliose, fruticose and some
crustose lichens specimens were collected from the islands and described by different authors. The first
comprehensive collection made, was provided during the Norwegian expedition to Tristan da Cunha in
1937-38 when mostly foliose and fruticose lichens were collected. From the collection of crustose
lichens, des Abbayes (1940) treated the genus Cladonia, and Lamb (1940) the genus Placopsis. The first
summary of lichens listed in publications (together with some unpublished identifications of Gough’s
species done by Mr. Peter James) was done by Wace & Dickson (1965, p. 353) who recorded 49 species.
Foliose and fruticose lichens from the first collection of Norwegian expedition, were later mastered by
Jørgensen (1977) who recorded 84 species from the Tristan group. He also stated that some of the listed
species by Wace & Dickson (1965) are either synonyms, incorrectly identified or of dubious status. He
also corrected his own findings later (Jørgensen 1979). It is worth mentioning that scientific knowledge
of the archipelago lichen flora is still developing as new species are being found and described, and so as
with some genera already known. A new collection was made during past two decades by Niek

14
Gremmen
1
. Specimens from both collections mentioned previously were studied, and a descriptions of
several new lichen species were published (Elix & Gremmen 2002; Elix et al. 2005; Øvstedal & Gremmen
2010; Elix et al. 2011). I combined all the publications listed and revised the lichen species for synonymy;
note that no classified lichenologist has checked this list (see Appendix 7.1). The total number of the
species in Appendix 7.1 therefore may be an overestimate of the real amount species recorded from the
islands, as I preserved doubtful records.
The discussion of the lichen flora found in this paragraph was done after the sources listed
(Jørgensen 1977, 1979; Ryan et al. 2007; Elix et al. 2005, 2011; Elix & Gremmen 2002; Øvstedal &
Gremmen 2010). Lichens are widespread on the islands, common on rocks along the coast as well as at
high elevations. Some of them live right on the ground (e.g., Stereocaulon spp. Hoffm., Parmotrema
perlatum (Huds.) Ach.), others can maintain it also on the roots of Spartina arundinacea (such as
Dirinaria applanata (Fée) Awasthi, which is the most variable there in habitat choice) growing from the
sea level. Others prefer to inhabit places, close to bird colonies, though are often fertilized, such as for
example Punctela canaliculata (Lynge) Krog (which is normally corticolous, on Gough Is. that is growing
on coastal rocks), Ramalina cf. laevigata Fr., R. scopulorum Ach., Parmotrema reticulatum (Taylor) M.
Choisy and Heterodermia speciosa (Wulf.) Trevis. Near the beaches Tephromela rimosula Øvstedal is
often found. Many lichens of the subgenus Parmelia are often found within the Settlement (Parmelia
microspore Müll. Arg., P. revolutella Nyll., which is an endemic species to Tristan da Cunha and St.
Helena, P. maura Pers., P. cetrata Ach. coll. and Parmotrema crinitum (Ach.) M. Choisy), while others
live just nearby ferns (e.g., Ramalina cf. linearis (Sw.) Ach., Peltigera dolichorhiza Nyl.). The most
common parmelioid species on Gough Island, Parmotrema reticulatum, prefers to live close to human
occupation, which couldn’t be overlooked as grows on the wooden stairs at entrance to base building
and also forms large clumps as common epiphyte in dense Phylica thickets. Among other common
species (on all islands and often not selective on materials) can be mentioned: Parmelia maura,
Parmotrema crinitum, P. perlatum and Dirinaria applanata, but also Leptogium denticulatum auct. non.
Nyl. (growing on low elevation on Phylica, Salix and apple trees) and Pseudocyphellaria intricata (Del.)
Vain.. However, on higher altitudes, common species are those of Ramalina Ach. or ‘Snow Lichens’ of
Stereocaulon, and other worth to mention since living inside the crater at 1950 m a.s.l. – Peltigera
friesiorum Gyeln., Stereocaulon glabrum (Müll. Arg.) Wain. and S. vesuvianum Pers., which is the most
widely distributed one reaching Spitsbergen in the Arctic Region, although many other extend as far as
Norway. Some species are restricted to these high levels and it won’t be surprising to find them
nowhere else but on the Peak of Tristan. Actually, as Wace & Holdgate (1958) stated, due the extreme
exposure, wind condition and the instability of volcanic cinders only some small fruticose and crustose
lichens can survive. Other lichen species use bryophytes in heights (e.g., Psoroma hypnorum (Vahl) S.F.
1
Niek J. M. Gremmen, NIOO Centre for Estuarine and Marine Ecology, Netherlands

15
Gray var. paleaceum (Fr.) Rostr. and Stereocaulon implexum Th. Fr.) to maintain it at more exposed
places, but grow on the ground/trees at lower elevations. However, there are some species such as
Massalongia griseolobulata Øvstedal, Parmotrema arnoldii (Du Rietz) Hale and Pseudocyphellaria
intricata, seeking for bryophytes anywhere, or some growing on peat surface in shady and humid places,
as Lepraria goughensis Elix & Øvstedal. Brook stones are often inhabited by Parmelia revolutella, P.
rockii Zahlbr., the endemic R. elegantula P.M. Jørg (also on the peak of Nightingale) and Usnea
vermicularis P.M. Jørg., rock faces by Parmelia spp., Ramalina spp., Usnea ceratina Ach. and endemic U.
nigropapillosa P.M. Jørg.. Not only bryophytes, but also Island Berries Empetrum rubrum are often
occupied by lichens (e.g., Parmeliella pycnophora (Nyl.) R. Sant., Polychidium dendriscum (Nyl.) A.
Henssen, Pseudocyphellaria intricata or Sticta ambavillaria (Bory) Ach.) as well as Bogfern’s stems of
Blechnum palmiforme (e.g., Hypotrachyna microblasta (Vain.) Hale, Parmotrema gardneri (C. W. Dodge)
Sérus. and Massalongia griseolobulata – endemic to Gough Is.) and Bogfern community (Leptogium
laceroides B. de Lesd., Hypotrachyna microblasta). However, the most overgrown by lichens are the
Island Trees Phylica arborea. Species of Parmelia, Sticta (e.g., Parmeliopsis afrorevoluta (K. & S.) Elix &
Hale, Sticta tesselata Øvstedal, S. fuliginosa Nyl. (Dicks.) Ach.) and Pseudocyphellaria are common
epiphytes; branches of many Island Trees are often densely covered by lichens. Some seek open Phylica
bush vegetation (e.g., Hypotrachyna bogotensis (Vain.) Hale, Sticta tesselata, Parmelia revolutella) while
others not so much (e.g., Parmotrema gardnei, Szczawinskia phylicae Øvstedal together with
Polychidium spp. (Ach.) Gray, Hypotrachyna endochlora (Leight.) Hale, Parmeliella nigrocincta (Mont.)
Müll. Arg. and Usnea dasycera (Nyl.) Mot.). Many species are reported from the Nightingale Lake region,
for example Heterodermia casarettiana (Mass.) Trevis., H. leucomela (L.) Poclt and H. endochlora,
Parmelia dilatata, Parmotrema perlatum, Ramalina celastri, R. peruviana Ach. coll., R. tayloriana Zahlbr.,
Teloschistes flavicans (Ew.) Norm., and Usnea ceratina which can also be found on exposed cliffs of
Nightingale. Parmotrema arnoldii, P. crinitum and also the recently found endemic to Gough Island,
Cresponea sorediata, often grow over dead Phylica wood and other plant remains.
BRYOPHYTES
MOSSES (MUSCI)
Mosses are, together with lichens, the most conspicuous terrestrial non-vascular plants on the Tristan
da Cunha archipelago. They are often found in high abundance on places where other plants do not
occur, especially due to extreme weather or habitat conditions, often in places similar to lichens. The
Scottish National Antarctic Expedition (April in 1904), Shackleton–Rowett Expedition (June, 1922) and
The Norwegian Antarctic Expeditions (1927–1928), made the first collections on the islands (reported
26 moss species in total), but the first comprehensive study was not made until the Norwegian
expedition to Tristan da Cunha in 1937–38, when probably more than 1000 specimens were collected by

16
E. Christophersen and Y. Mejland (Dixon 1960). The largest contribution to our knowledge of the moss
flora on the archipelago was certainly made by Edwin B. Bartram (in Dixon 1960; Bartram 1959) and
H.N. Dixon (Christophersen 1934; Dixon 1960). The only other contribution was that of Wace & Dickson
(1965) who published a table of moss species based on Dixon (1960) and also on the personal collection
of N.M. Wace on Gough Island and Tristan in 1955-56. Unfortunately, from the 1960s, only two, smaller,
publications appeared (Ochyra 1999; Dickson 1967) containing remarks on mosses of the archipelago. It
is possible that others exist, but up to now, we were unable to trace any. For the list of moss species
present, see Appendix 7.2. I kept the doubtful records, but marked them with a question-mark. As is
reported in Ryan (2007), the total number of moss species should be at least 150 which agree with
number of species in Appendix 7.2, but the total number of species present may be much higher as the
islands are still under-collected.
The discussion of the observed moss flora in this paragraph is based on the sources listed: Ryan et
al. 2007; Wace & Dickson 1965; Bartram 1959; Dixon 1960; Christophersen 1934; Wace 1961; Glass et
al. 2006. Mosses are widespread on the archipelago; as epiphytes, in gulches, on moist rocks, covering
ground beneath the vascular plants, or as dominant plants higher in the mountain. However opposite of
lichens, mosses are rather not in areas heavily influenced by sea spray. If they occur by the sea, they
often choose cave walls (Fissidens leptochaete Dus., Amblystegium patenti-flexuosum Dixon, Bazzania
skottsbergii (St.) Fulford., Rigodium crassicostatum (Dix.) Bartr., and Cyclodictyon laete-virens (Hook. &
Tayl.) Mitt. the ‘Bright Green Cave-Moss’), sea cliffs (Bryum tenellicaule Card.) or wet rocks opposite to
salt spray (Pohlia wahlenbergii (Web. & Mohr) Andr., Drepanocladus fluitans (Hedw.) Warnst.). Some
can also be found on the wet sand ground (Dicranella hookeri (C. M.) Card.), further from the sea
(Trichostomum aequatoriale Spr.) or on the edge of the beach (Brachythecium subpilosum (H.f. & W.)
Jaeger). Also waterfalls ending near the sea and running water on beaches are often occupied by
mosses, attached to wet stones (Breutelia popinqua Kaal., Brachythecium subpilosum, Racomitrium
lamprocarpum (Müll. Hal.) Jaeg.) or growing in the running water (Pohlia excurrens (Dixon) E.B. Bartr.,
Philonotis tenuis (Tayl.) Jaeg., P. vagans (H. & W.) Mitt. and Bryum fluitans Dixon, the true aquatic
species). Species that prefer aquatic habitats occur at lower altitudes (up to 600 m). These can be found
in (or just by) brooks and streams (the endemic Funaria euryloma Dixon, Bartramia patens Brid., the
probably entirely aquatic Fissidens fluitans Dixon or recorded as floating masses, Hypnum cupressiforme
Hedw., Rhynchostegium irriguum Dixon and Trematodon intermixtus Card.), on the edges of ponds
(Blindia subcapillifolia Dixon, Dicranella vaginata (Hook.) Card., Dicranoloma perdecurrens Dixon, this
one also occurs up to 2000 m) or on dripping stones, basically at any altitude where they occur (e.g.,
endemic Bryum subantarcticum Dixon, Didymodon austroalpigena (C.M.) Broth., Pleuropus bonplandi
(Hook.) Broth., Philonotis vagans, Psilopilum laxifolium Dixon, Racomitrium nigritum (C.M.) Jaeg.).
However, the habitats in upland areas of the two larger islands are subject to drier conditions. Plant
species there are often exposed to desiccation stress when growing on rocks, on relatively dry soil, or in

17
open vegetation. Species of Racomitrium are well-adapted to the rough weather conditions and are
important pioneers to colonize, and also stabilize, some of the cinder slopes (R. lanuginosum (Hedw.)
Brid., also known as ‘wooly moss’, R. laevigatum A. Jae., R. crispulum (H.f. & W.) H.f. & W., and the
endemic R. gracillimum Dixon; at least the last two were also found at the highest point of the peak).
Likewise abundant are the granite mosses Andreaea spp., forming dense reddish or black cushions on
rocks at high altitudes (the endemic A. atlantica Dixon, A. grimmioides Dus. and two other often
abundant in crater of the Peak: Andreaea parallela C.M. and A. regularis C.M.) and others (e.g,
Chrysoblastella chilensis (Mont.) Reimers, Ditrichum hyalinum (Mitt.) Par., endemic Ditrichum tenuinerve
Dixon, Hennediella kunzeana (Müll. Hal.) Zand., with some of Thuidium spp., Tortula spp., and
Polytrichum spp.). In the upper parts of Tristan (from 1200 m), mosses are important habitats for some
lichen species (e.g., Psoroma hypnorum var. paleaceum, see above) and are also often found in
association with flowering plants (Racomitrium crispulum, R. lanuginosum and various Dicranaceae).
Empetrum heath, present from low levels to some 1200 m a.s.l., is also hospitable for mosses, abundant
beneath the berry species (for example, endemics Bryum cymbifoliellum Dixon, Campylopus
alienus Dixon and Psilopilum tristaniense Dixon). Also mosses occur on trunks, branches and twigs of
Phylica trees, but not in such high abundance as lichens, this includes for example Campylopus
pyriformis (Schultz) Brid. (also in Scirpus tussocks), Hypnum chrysogaster Müll. Hal., and endemics
Macromitrium antarcticum C.H. Wright, Zygodon insularum Dixon and
Rhynchostegium isopterygioides Card. The shades of the tree-fern community are also used by others,
namely Dicranoloma spp., the endemics Dicranodontium tristaniense Dixon & Thér. and
Daltonia tristaniensis Dixon, Dicranella hookeri, Chorisodontium aciphyllum (H.f. & W.) Broth.,
Bartramia ithyphylla Brid. and the endemic Breutelia tenuifolia (Mitt.) Par. In association with Scirpus
tussocks, often on roots, others can be found (e.g., Ceratodon purpureus (Hedw.) Brid, ). Other habitats,
where mosses are dominant, are valley and plateau bogs and especially those on the southern Gough
Island. Sphagnum species are the principal peat-forming plant there, and form large tufts in pioneer
vegetation on recent peat-slips (e.g., very abundant S. recurvum Beauv). Ptychomnion densifolium (Brid.)
Jaeg., Racomitrium lanuginosum, Sphagnum magellanicum Brid., S. fimbriatum Wils., Campylopus
richardii Brid., Braunia humboltii, and the endemic Dicranodontium tristaniense, are the ones that
typically form valley bogs. The plateau bogs (at approximately 600 – 700 m) forms a more humified peat
than the valley bogs. Dicranoloma spp., Braunia humboltii are important species there, together with
numerous small hepatics. Sphagnum spp., although still in large amount, are less important there.
Eventually, some species that can be found in the Settlement, within the pastures, grasslands or potato
patches, are for example theendemic Amblystegium stricto-serpens Dixon, Bartramia ithyphylla Brid.,
Bryum amplifolium Dixon, B. truncorum Brid., Ceratodon purpureus, Funaria euryloma, Leptodontium
interruptum (Mitt.) Broth. and Orthotheciella varia (Hedw.) Ochyra.

18
LIVERVORTS (HEPATICAE) AND HORNWORTS (ANTHOCEROTAE)
Liverworts and hornworts are the best discussed group of bryophytes, and maybe also of non-vascular
plants in general. The first comprehensive collection was also done by the Norwegian expedition
between Dec 1937 and Mar 1938. Specimens from the expedition were mostly identified by S.W. Arnell
(Arnell 1958), who also determined the collection of N. Wace after the Gough Island Scientific Survey
(Oct 1955–Mar 1956). Other expeditions that contributed to the collection of liverworts and hornworts
were done by N.J.M. Gremmen (Sep 1999, Jun–Sep 2000, Sep 2005, and Nov 2007–Feb 2008) and these
were determined by John J. Engel
2
and Jiří Váňa
3
, both also did the identification of many smaller
collections throughout last 60 years. After their venerable work on hepatics from the Tristan da Cunha
archipelago (Engel 1977; Váňa 1998), they managed to published ‘memoirs’ The Liverworts and
Hornworts of the Tristan da Cunha Group of Islands in the South Atlantic Ocean (Váňa & Engel 2013),
where all species known are gathered along with literature records and ecology, together with findings
of distribution and a history of exploration. Complete knowledge of this plant group can be found in the
publication, as well as lists of all taxa reported from the archipelago throughout the time (p. 123–125
and 131–135).
Liverworts have the majority of taxa known in this group from the archipelago. Only four species
of hornworts are reported, two of them as endemic (Anthoceros patagonicus Häss. subsp. gremmenii
J.C. Villarreal, J.J. Engel & Váňa, subsp. nov. and Anthoceros tristanianus J.C. Villarreal, J.J. Engel & Váňa,
sp. nov.). The following short discussion of the occurring liverworts and hornworts on the islands is
based predominantly on the publication of Váňa & Engel (2013) and references therein (Wace 1961;
Wace & Dickson 1965; Ryan et al. 2007). Hornworts usually grow in large mats in wet and shaded
environments, mostly in the lowlands near streams, but A. patagonicus is also known from its
occurrence on the top of a new volcano (1600 m). The main feature of the hepatic flora is the large
number of leafy species which are epiphytic on the trunks of Blechnum palmiforme (e.g., Adelantus
lindenbergianus (Lehm.) Mitt., Bazzania peruviana (Nees) Trevis., Chiloscyphus textilis (H.f. & T.) J.J.
Engel & R.M. Schust., endemic Ch. wacei S.W. Arnell ex J.J. Engel et Váňa) and Phylica arborea (e.g.,
Chiloscyphus subporosus (Mitt.) J.J. Engel & R.M. Schust., Cololejeunea microscopica (Taylor) Schiffn., the
endemics Plagiochila tristaniana Váňa & J.J. Engel and P. wacei S.W. Arnell ex Váňa & J.J. Engel) in the
fern bush vegetation
4
. The liverwort species are most abundant in lowlands, where they seek for damp
environments. But they also occur in upland’s mires (e.g., Anastrophyllum auritum (Lehm.) Steph.,
Chiloscyphus otiphyllus (H.f. & T.) J.J. Engel & R.M. Schust., Metahygrobiella tubulata (H.f. & T.) R.M.
Schust., Perdusenia rheophila Hässel) and plateau bogs (e.g., Allisoniella subbipartita (C. Massal.) R.M.
2
Dr. John Jay Engel, Department of Botany, The Field Museum of Natural History, Chicago
3
Prof. Dr. Jiří Váňa, Department of Botany, Charles University in Prague, Czech Republic
4
Many of species listed are common in tree-fern-bush vegatation and their occurrence on both, Blechnum and
Phylica, are not an exception.

19
Schust., Blepharidophyllum densifolium (Hook.) Angstr. ex C. Massal., that is nearly restricted to Gough’s
bogs, than Cephalozia species (Dumort.) Dumort., forming dense mats that completely overgrow the
Sphagnum, Herbetus sendtneri (Nees) Lindb., and the bog’s dominant Syzygiella colorata (Lehm.)
Feldberg). More in uplands, hepatics occur on rocks among mosses, for example, Andrewsianthus
marionensis (S.W. Arnell) Grolle, Frullania magellanica F. Weber & Nees subsp. tristaniana (S.W. Arnell)
Váňa & J.J. Engel (endemic and very common on montane rock), Plagiochila wacei and Syzygiella
colorata), but also on rock slopes such as Frullania brasiliensis Raddi and Metzgeria leptoneura Spruce.
Nevertheless, hepatics are specialized to lowlands and especially to its coastal tussock vegetation (e.g.,
Calypogeia annabonensis Steph., Cephaloziella spp. (Spruce) Schiffn., Chiloscyphus coadunatus, the
endemic Ch. tristanianus (S.W. Arnell) J.J. Engel & R.M. Schust., Telaranea breviseta (Herzog) J.J. Engel &
G.L.S. Merr) and moist or hydric niches (e.g., Aneura subcanaliculata R.M. Schust., Chiloscyphus spp.
Corda; Dumortiera hirsute (Sw.) Nees, Phaeomegaceros plicatus (Mitt.) J.C. Villarreal). When occurring
by the water, they are also found in the Settlement such as Anthoceros patagonicus, Linularia cruciate
(L.) Dumort., Phaeomegaceros plicatus and the genus Marchantia L., which often seeks for nutrient-rich
habitats and is abundant in dense mats in areas with large numbers of seabirds or seals. Some of the
most common species of the archipelago are, for example, Adelantus lindenbergianus, Anastrophyllum
involutifolium (Mont. ex Gottsche et al.) Steph., Bazzania peruviana, Chiloscyphus coadunatus (Sw.) J.J.
Engel & R.M. Schust., endemic Ch. granditextus Steph., Ch. serratus (Mitt.) J.J. Engel & R.M. Schust.,
Lepidozia laevifolia (H.f. & T.) Gottsche et al., and Syzygiella colorata.
ALGAE
Another important group among terrestrial non-vascular plants are the limno-terrestrial and freshwater
algae (including Cyanobacteria). Although marine algae and seaweeds were collected and reported in
past and are known in outline, our knowledge of the non-marine algal flora is limited and still in a
preliminary stage (Wace & Dickson 1965; Ryan et al. 2007). In fact, only terrestrial and aquatic diatoms
have been intensively collected, identified and published (Carter 1966; Van de Vijver & Kopalová 2008);
173 taxa were reported by Carter (1966), of which 56 as new species whereas one new species was
described by Van de Vijver & Kopalová (2008). Additionally, diatoms were listed during paleo-studies
that took place on Tristan da Cunha (Holmgren et al. 2011), Inaccessible (Preece et al. 1986) and
Nightingale (Holmgren et al. 2013). Nevertheless, only one detailed taxonomic study was done on
diatom flora, by John R. Carter who analyzed 12 samples, of which ten were collected during the Royal
Society Expedition (in 1962) on Tristan da Cunha and the two remaining were collected from Gough
Island during the Gough Island Scientific Survey (in 1956). Furthermore, other collections were recently
made by N.J.M. Gremmen, who collected more than 250 samples from Gough Island. Based on material
from this collection, so far one new species was described (Van de Vijver & Kopalová 2008), but since
then the collection remained virtually unstudied.

20
Apart from the diatom flora, the following terrestrial algae and Cyanobacteria were reported by
Wace & Dickson (1965), Wace (1961) or Váňa & Engel (2013), and here are presented as short listing:
i.e., species of Gloeocapsa Kützing and Scytonema C. Agardh ex Bornet & Flahault, both amongst lichens,
Nostoc colonies (perhaps N. fuscescens F.E. Fritsch) irregularly scattered on the ventral side of hornwort
Anthoceros patagonicus, Trentepohlia spp., which is conspicuous on Gough Island; the rest was collected
by J.H. Dickson – species of Stigeoclonium (perhaps S. tenue Kützing), Oedogonium sp. Link ex Hirn,
Spirogyra sp. Link, Zygnema sp. Agardh and Nostoc sp. Vaucher, all were gathered from habitat of new
lava field near the Settlement (1962), and Schizothrix cuspidata W. & G.G. West, which grew by the
waterfall).
DIATOMS (BACILLARIOPHYTA)
The study sites studied by Carter (1966) included: rocks in running water at the sea level, salt beach,
stones in lowland streams and gulch stream (about 550 m), Crater Lake (1981 m; moss or algal habitat),
lowland stream pool, new lava field and other from Gough Island – Cave Bell Rocks at the sea level and
lowland stream Gonydale (500 m). The most abundant (in terms of number of species) genera were
Achnanthes, Eunotia, Navicula, Nitzschia, and Pinnularia. The most common taxa in the samples were
for example, Achnanthes lanceolata (Bréb.) Grun., A. minutissima Kütz., Fragilaria bicapitata A. May.,
F. construens (Ehr.) Grun., Gomphonema parvulum (Kütz.) Grun., Navicula contenta Grun., N. mutica
Kütz., and Pinnularia subcapitata Greg., of which only N. mutica was found on both islands.
Genera and taxa reported by Carter (1966) are discussed in this paragraph, with respect to
localities where they were observed and also with notes from paleo-studies. The salt beach site was
inhabited mostly by Achnanthes spp., Fragilaria spp., Gomphonema spp., Navicula spp., and Nitzschia
species, of which some, for example, Achnanthes natrata Carter and Pinnularia tropica Hust., were not
reported from other sites. Interestingly, other species of this site were also quite abundant in cores from
the Inaccessible Bog’s sites, for example Eunotia exigua (Bréb.) Rabh, Fragilaria brevistriata Grun. and
Navicula mutica Kütz. (Preece et al. 1986). Many taxa observed on this site also occur on new lava field
(e.g., Nitzschia petulla Carter, Pinnularia biceps Greg. or Synedra ulna (Nitzsch.) Ehr.), and some of
Gomphonema and Achnanthes were also found on stones in running water (sea level). Species found
often in streams belonged to the genera Eunotia, Frustulia, Gomphonema, Melosira (often on Gough’s
sites) and Navicula (e.g., Frustulia rhomboides (Ehr.) de Toni (also reported from the core of 2nd Pond on
Nightingale (Holmgren et al. 2013), Gomphonema parvulum (Kütz.) Grun. and Navicula contenta Grun.).
The one discern locality from listed sites above on Tristan da Cunha, is the one of Crater Lake (1981 m),
where diatoms were collected from moss and algae. The species found there were often not reported
from other sites (e.g., Achnanthes atalanta Carter, Denticula tenuis Kütz., Eunotia incurva Carter,
Navicula gracilis Carter, Synedra amphicephala Kütz.) and some otherwise common genera to Tristan
Island are totally absent in samples from this locality (Gomphonema spp., Melosira spp., Nitzschia spp.

21
and except for two taxa, also Pinnularia spp.).
Except for the species Navicula mutica (abundant in samples), Pinnularia dispersa Carter and
three other taxa, Gough Island presents quite a different diatom flora compared to Tristan da Cunha, at
least, according to Carter’s findings. Above that, results from two paleo-studies (from Tristan, but also
from Nightingale Island) did not revealed any shared taxa (Carter 1966; Holmgren et al. 2013; Holmgren
et al. 2011). According to the paleobotany study of Preece et al. (1986), four species were reported in
common with the remaining island from the archipelago, Inaccessible (Melosira setosa Carter,
Orthoseira roseana (Rabenhorst) O'Meara, Pinnularia microstauron (Ehr.) Cl., Pinnularia restituta
Carter). Nevertheless, a strong correlation can be seen, between those reported from Inaccessible and
those from Tristan da Cunha. Noteworthy is, that both studies of diatom material, from Gough and
Inaccessible, were made by Carter and described similarly, though the botanical nomenclature and
taxonomy used is not up to date with the remaining recent studies. The two studies of Holmgren et al.
(2011, 2013) mainly reported diatom species that have not been found on the islands before. Only P.
viridis (Nitz.) Her (a species typically found in peat bogs) and Frustulia rhomboides were also found by
Carter on Tristan da Cunha, but otherwise 16 species and five varieties were reported for the first time.
A possible explanation is that these new findings were made in a habitat that was not studied so far:
stagnant pools (2nd Pond and Bottom Pond), as many new genera for the archipelago were reported,
such as for example the meroplanktonic Aulacoseira, as well as the terrestrial and aerophytic genera
Diadesmis, Luticola and Kobayasiella, together with the benthic genus Psammothidium and the
epiphytic genus Chamaepinnularia. The 2nd Pond on Nightingale was classified as an oligotrophic bog or
wetland, with fluctuating water levels throughout most of the Holocene as no planktonic or
meroplanktonic taxa were found in the sediment core (Holmgren et al. 2013). Bottom Pond on Tristan
da Cunha is a slightly acidic, oligotrophic pond with deep water, dominated by the meroplanktonic
genus Aulacoseira, e.g., Aulacoseira alpigena (Grun.) Krammer and A. distans (Ehrenberg) Simonsen
(Holmgren et al. 2011).
Although many genera and species, new to the archipelago, were observed, this was not the main
objective of these paleolimnological studies. Based on the changes in the diatom flora and the peat
content in cores from the ponds of Tristan da Cunha and Nightingale, many of local and some regional
events were revealed. The authors identified phases of increased local erosion and precipitation,
changes in water level or even suggested dry conditions in the early Holocene. When compared with a
multi-proxy study of the environmental changes on Tristan da Cunha, the perhaps most distinct peak of
terrestrial diatom concentrations observed by Holmgren et al. (2013) coincides with the 8.2 ka BP cold
event in the North Atlantic, as is suggested by Ljung et al. (2006). The comparison of the two studies by
Holmgren et al. can also reveal a period of increased precipitation in the Tristan da Cunha region at c.
2200–1700 cal a BP. This is suggested by the authors as an effect of a northward shift of the Southern

22
hemisphere west wind belt around 2000 cal a BP, thereby placing the Tristan da Cunha archipelago in a
more central position affected by more and more intense storms.
4 DISCUSSION
The following discussion presents a synthesis of the known information about each observed plant
group, its endemism and world distribution. Total numbers can be seen in the Table 4.1. This includes a
total number of taxon present for each plant group, along with a percentage of endemism.
Biogeographical position of the Tristan da Cunha archipelago is based on distributional patterns in each
discussed plant group.
TABLE 4.1 - Total numbers (taxon level) for each non-vascular plant group + calculated endemism.
Lichens
Mosses
Liverworts and Hornworts
Diatoms
TOTAL
Number of taxa
125
156
145
232
658
Number of endemic
14
49
18
56
137
% of endemism
11,20
31,41
12,41
24,14
20,82
The geographical relationship of the vegetation on the archipelago is clearly set by conspicuous
vascular plants. Tussock grassland is clearly related to the sub-Antarctic insular vegetation, together
with Spartina arundinacea, structurally similar to the Amsterdam–St. Paul island group. The fern-bush
vegetation of Phylica arborea and Blechnum palmiforme resembles the communities that can be found
in the upper limit of the woody vegetation in tropical mountains, e.g., East African, Jamaican, Tasmanian
and New Zealand mountains (the structural equivalent of the typical composition of the archipelagos
fern-bush vegetation, is well-present in Wace & Dickson (1965, p. 323)). A strong indication of the
closest connection with South America is given by lichens, mosses, liverworts and hornworts, as would
be discussed below, to prove the dispersion through prevailing western winds – ‘West Wind Drift’ (see
p. 2 of this thesis) (Galloway 1996; Milius 2004; Muñoz et al. 2004). This connection is so strong, that
even Skottsberg (1960) had to admit the existence of overseas migration. The existence of long-distance
dispersal is also suggested, for example, by the paleobotanical study from Inaccessible Island, which
revealed ‘exotic’ taxa such as Ephedra and Nothofagus in low numbers (Preece et al. 1986). The
connection with South America is conspicuous in all groups of non-vascular plants, except for algae of
which only diatoms were described, although the actual records are not sufficiently accurate to make
proper comparisons. Therefore, diatoms were only compared to some islands across the South Ocean,
more as an illustration than as an accurate revision.
LICHENS
The level of endemism in the lichen flora of the archipelago is not clear. It is generally surprisingly
lower than on islands elsewhere, as stated by Jørgensen (1977), about 5 % of the island species are

23
endemic. However, thenceforward some new representatives were discovered, and this movement may
continue in future research. Accepting the newly discovered species as endemics and with the total
number of species from Appendix 7.1 (125), this brings the endemic level up to 11,2 %. Nevertheless,
only time and further collecting will show, because some of them are supposed to be easily dispersing
(e.g., the sorediate Caloplaca austroatlantica Øvstedal). In general, lichens seem more widespread than
other plants and show less tendency to form local endemism, but they’re also especially vulnerable to
air condition, though repeated volcanisms may have destroyed the lichens more than other plant groups
(Jørgensen 1977). From the records mentioned, the resemblance between the Gough and Tristan group
based on lichens is undeniable (Jørgensen 1977, 1979; Elix & Gremmen 2002) but this can be also
disproved by other newly described species, as Øvstedal & Gremmen (2010) already added a few (4 to
Tristan and 3 to Gough). In addition to, clear affinities are visible to South America (Jørgensen 1979; Elix
& Gremmen 2002) as can be seen in the genera Cladonia and Stereocaulon, as well as on some typical
species Punctelia canaliculata, Hypotrachyna bogotensis and H. microblasta. Only a few species have not
been recorded there yet (e.g., Dirinaria applanata, Heterodermia casarettiana, Stereocaulon meyeri
Stein and Physcia erosula Nyl.) and beyond that, quite a number are restricted to the archipelago and
the Magellanic region of the southernmost South America, which is also supported by other plant
groups (Jørgensen 1979). As is mentioned above, west winds works well in distribution of lichens, from
South America to the Tristan da Cunha archipelago. The example of wind-connection can also be seen
on the Bouvet Island on one side, and Ile Amsterdam and St. Paul on the other. The sub-Antarctic
Bouvet Island, which is only some 1,860 km away from Gough Island, shares no lichens (Muñoz et al.
2004); but Gough has approximately 18 lichen species (or even more) in common with the 7,400 km
distant Amsterdam–St. Paul island group (based on Appendix 7.1 and Aptroot et al. 2011). Obviously not
the distance, but being right on the West Wind Drift (and not interrupted by any continent, as Africa is
northerly) can provide distant islands with common species that are not necessarily are only lichenous.
The lichen species recorded, range in origin from tropical (often mountainous places) across subtropical
(eg Dirinaria applanata, Pyxine cf. cocoës) to temperate (Elix & Gremmen 2002), with only the rare
exception of Stereocaulon vesuvianum that reaches the Arctic (see above).
MOSSES
The level of endemism in the moss flora of the archipelago is currently unknown. According to
Dixon (1960) the number of endemic species is larger than actually accepted. He reported 128 species
from which 59 were endemics to the islands (46 % of the native flora). This was marked by Jørgensen
(1979) who studied lichens, as ‘an alarmingly higher percentage of endemism’. Likewise, in Wace &
Dickson (1965), the level of endemism was estimated at 43 % for the mosses. This shows that the level
of moss’s endemism is higher than in other plant groups, to which probably only pteridophytes can
compete. After the revision of reported species, with the total number of species from Appendix 7.2

24
(156), the level of endemism now is close to 32 %. This supports Dixon’s (1960) opinion that a certain
number of the endemic species may be discovered elsewhere later, but it is difficult to say since no new
records are out.
Although mosses can easily spread through spores, vegetative structures, or even can regenerate
from tiny broken-off pieces, many of them have a very limited range (Frahm 2007; Milius 2004). The
Tristan da Cunha archipelago reflects some distributional patterns on the composition of moss species.
The connection of Tristan group and further Gough Island is obvious, they share many Hypnum spp.,
Dicranoloma spp., Pohlia spp. and Campylopus species, and also some endemics (Macromitrium
antarcticum, Philonotis capillata Mitt., Pohlia excurrens, Rhynchostegium isopterygioides). As well as in
lichen species, the connectivity throughout the ‘West Wind Drift’ is clearly visible. This supports a
prevalent number of species common to the archipelago and to the southernmost South America (Dixon
1960; Ochyra 1999) for example, Andreaea grimmioides, Brachythecium austroglareosum (Müll. Hal.)
Kindb., Bartramia patens, Dicranella fuegiana Card. & Broth, Dicranoloma spp., Philonotis vagans,
Racomitrium spp. Another statement of Dixon (1960) was that a clear evidence of connection with the
South African flora is absent, but for example Dicranella hookeri (C.M.) Card. (a pan-south-temperate
species) was recently recorded in South Africa (Ochyra et al. 2013). This and also some others (e.g.,
Chrysoblastella chilensis) can present the progressive spread of species from the West. Nevertheless,
some 14 species are of almost cosmopolitan range; worth to mention that apart from them, no species
of Palearctic or Holarctic distribution is known from the islands (Dixon 1960). Also no record of moss
introduction by human to the archipelago is known, apart from one of Pseudoscleropodium purum
(Limpr.) Fleisch., which was used as packing material and arrived from St. Helena (Dickson 1967).
LIVERWORTS AND HORNWORTS
The level of specific endemism in the Liverworts and Hornworts flora has been estimated by Wace
& Dickson (1965) to 14 % of the total flora. Váňa & Engel (2013), after their comprehensive study,
reduced this number slightly, to 18 taxa and 12,41 % respectively. But they also described two new
genera, five species and two intraspecific taxa, in total nine new combinations.
Among liverworts and hornworts, Váňa & Engel (2013) recognized 145 taxa present on the Tristan
da Cunha archipelago. This indicates a great revision of the species reported earlier, as both Wace &
Dickson (1965) and Ryan (2007) stated more (160, and some 165); although, still some doubtful records
are indicated which should be verified more in future (Váňa & Engel 2013). The species present on the
archipelago show some distributional patterns which partly also reflect patterns of lichens and mosses.
The strongest correlation of liverworts and hornworts flora of the Tristan da Cunha archipelago is some
37,93 % shared taxa with ‘temperate regions of South America’. This means the Magellanian region (but
without Tierra del Fuego), Valdivian region, a combination of both and the Andes. As follows, every
region is listed with its representatives in brackets: Magellanian region (Chiloscyphus patulistipus

25
(Steph.) J.J. Engel & R.M. Schust., Perdusenia rheophila Hässel; 10 taxa in total), Valdivian region
(Metzgeria epiphylla A. Evans; 13 taxa) and a combination of both (Ch. textilis, Kurzia saddlensis (B. & C.
M.) Grolle; 26 taxa), also the Andes (Microlejeunea bullata (Taylor) Steph.; 6 taxa). Among the regions
listed are also distributed some taxa from: Juan Fernández Island (Bazzania peruviana, Riccardia
tristaniana S.W. Arnell; 42 taxa), Falkland Island (Leptoscyphus aequatus (H.f. & T.) Mitt.) and South
Georgia. Interesting is the correlation between the Tristan Group and Juan Fernández Is. with 29 % of
common taxa; Valdebenito et al. (1990) also well documented this connection on the inter-population
disjunction for Peperomia (Piperaceae). Other noteworthy phytogeographical patterns are those of
Amphiatlantic temperate (7,58 %), Amphipacific temperate (5,52 %), Sub-Antarctic (5,52 %), and
Tropical (11,04 %; including tropical taxa from America, Africa, Paleotropical and Pantropical). On the
other hand, not many are restricted (2 %) to the Australasia region (New Zealand + Tasmania), only
three taxa with Oceania (absent from the sub-Antarctic islands), two taxa are of Bipolar distribution, and
also the correlation with Ile Amsterdam–St. Paul group of islands is not strong. The archipelago has
some 11 species in common with Ile Amsterdam (10) and St. Paul (1), mostly with an Amphiatlantic,
Amphipacific (Lepidozia laevifolia) or Pan–South Temperate (Anastrophyllum auritum) distribution (Váňa
et al. 2010; Váňa & Engel 2013), and no uniquely shared species, but not many records can be found on
this plant group from this South Indian Ocean island group.
DIATOMS
The samples studied by Carter (1966) from Tristan da Cunha Island and Gough Island, revealed 56 new
species which were described by the author. On Gough respectively, genera with most species are
Melosira, Navicula and Pinnularia; note that many of them were newly described by Carter. The author
found a very distinct and highly specific diatom flora on Gough Island, with many new species (as 24 of
all newly described species were from Gough) that so far haven’t been reported from elsewhere (Van de
Vijver & Kopalová 2008). From the other studies dealing with diatoms it is clear that the diatom flora is
particularly diverse on the archipelago, with 203 species (plus another 29 forms and varieties) in 38
genera present. This number of species is an expected one, based on the diversity on other Southern
Ocean islands (Ryan et al. 2007). However, the majority of species is reported from localities of the
Tristan Group, leaving only 42 species reported from Gough Island, 41 by Carter (1966) plus Orthoseira
gremenii (Van de Vijver & Kopalová 2008). Out of this, only 12 species are shared between Gough and
Tristan Group. The level of endemism is certainly not clear for diatoms, only the above-mentioned
publications revealed new species to the archipelago, and these by Carter (1966) are not easily
understand because all of them were only illustrated by one or a few small drawings (Kopalová et al.
2008). Accordingly, the level of endemism shown in Table 4.1 (at the beginning of the Discussion, p. 22)
has to be taken with some respect.
The diatom taxa observed in Bottom Pond (Tristan da Cunha) seem to have a high correlation to

26
taxa in the sub-Antarctic areas (Ile de la Possession, Prince Edward Islands, Marion Island) including both
cosmopolitan and southern hemisphere taxa (Holmgren et al. 2011; Van de Vijver & Beyens 1999). A
comparison between other islands revealed low similarity values. I compared the Tristan Island Group
(Tristan da Cunha, Nightingale and Inaccessible Island together) and Gough Island with sub-Antarctic
Marion and Prince Edward Island (Van de Vijver, Gremmen, et al. 2008), Ille Amsterdam in South Indian
Ocean (Chattová et al. 2014; Lowe et al. 2013) and with James Ross and Livingston Island from Maritime
Antarctica (Kopalová et al. 2014). The results of taxa they have in common are summarized below, in
Table 4.2.
Table 4.2 - Number of taxa in common; the Tristan da Cunha Island Group and Gough Island
compared with selected localities in South Atlantic and South Indian Ocean.
Marion + Prince
Edward Island
Ile Amsterdam
James Ross +
Livingston Island
Tristan Island Group
26
13
9
Gough Island
2
1
1
Tristan Island Group + Gough Island
1
2
0
Tristan da Cunha archipelago
29
16
10
Generally, most of the species shared by these localities are of cosmopolitan range. Many taxa shared
are not reported by Carter (e.g., Diadesmis ingeae Van de Vijver, Luticola muticopsis (Van Heurck)
Mann), except for taxa from Ile Amsterdam (Chattová et al. 2014; Lowe et al. 2013; Carter 1966). Among
those belongs for example, Gomphonema parvulum (Kütz.) Grun., Nitzschia frustulum (Kütz.) Grun. or
Pinnularia microstauron (Ehr.) Cl. Other noteworthy genera in common with Ile Amsterdam are
Melosira, Gomphonema, Navicula and Nitzschia, with the composition of species closer to Gough Island.
Many of species are similar with Prince Edward Islands – for example, Caloneis bacillum (Grun.)
Mereschk., Diadesmis langebertalotii Le Cohu & Van de Vijver, Frustulia vulgaris Thw., Melosira varians
Agdh. or Pinnularia intermedia Lagerstedt (Van de Vijver, Gremmen, et al. 2008). Only some are similar
to Maritime Antarctic region, but genera such as Diadesmis (e.g., Diadesmis contenta (Grun.) Mann) or
Luticola can be found (Kopalová et al. 2012, 2014).
The distribution of micro-organisms, such as algae, is presently the subject of a lively debate.
Accordingly to diatoms, with the ‘Ubiquity theory’ on one side (Finlay 2002) and ‘Biogeography theory’
on the other (Vyverman et al. 2007). The first view is that micro-organisms have unrestricted dispersal
capacities, thus could be everywhere as cosmopolitans, the other one is that at least some of them, such
as diatoms, has dispersal limited and can be also endemic. The Tristan da Cunha archipelago, with so
many species newly described by John R. Carter, and also with the recent collection, has a potential to
add a significant piece in this puzzle.

27
5 CONCLUSION
This thesis focuse on the non-marine non-vascular plants from the archipelago Tristan da Cunha located
in the South Atlantic Ocean. Despite its very interesting geographical position, its oceanic origin and
number of interesting habitats, most of the non-vascular flora of the archipelago is only limitedly
known.
However, out of this is a plant group of Liverworts and Hornworts, with its recent comprehensive
publication of Váňa & Engel (2013). The authors determined large amount of specimens from recent
collections of N. Gremmen and several others, which led to the examination of a great majority of
collections made in the archipelago before. This collection of N.J.M. Gremmen also allowed identifying
many new species of lichens, which are the other quite well-known group, but with no comprehensive
study or revision of earlier reported species. Although mosses are conspicuous plants on the islands,
forming bogs or mountain habitats, only few publications of its flora can be found. Maybe a new
collection, but certainly a proper revision of the moss flora is well-needed as the current list of known
species is quite confusing due to a lot of synonymous and taxonomical updates and even errors (Frahm
2007). Group of non-marine algae is certainly the most understudied at all. Except for diatoms, only a
few lines can be told about the algal group. Although some comparison could be made on the diatom
data from the Tristan da Cunha archipelago, the validity of these comparisons is questionable. Only a
revision of species described by Carter (1966) including a reanalysis of these using modern light and
scanning electron microscopy would enable other work with diatoms. Furthermore, the results of this
reanalysis might be then used to study the diatom diversity in a set of more than 250 recently collected
samples from Gough Island. This would allow a biogeographical comparison between Gough Island and
other localities in the Southern hemisphere, which is well-needed in the light of ongoing research on the
biogeography of diatoms related to questions about Ubiquity theory. Hopefully, this will be a challenge
for my master thesis next year.

28
6 REFERENCES
Aptroot, A., Van de Vijver, B., Lebouvier, M. & Ertz, D., 2011. Lichens of Ile Amsterdam and Ile Saint Paul
(TAAF, southern Indian Ocean). Nova Hedwigia, 92(3), pp.343–367.Bartram, E., 1959.
Contribution to the mosses of Gough Island. Revue Bryologique et Lichenologique, 28, pp.208–
210.
Bennett, K.D., Gribnitz, K.-H. & Kent, L.E., 1989. Pollen analysis of a Quaternary peat sequence on Gough
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7 APPENDICES
APPENDIX 7.1 - List of 125 lichen taxa reported from the Tristan da Cunha archipelago.
NOTE: * endemic; **endemic to Tristan da Cunha and St. Helena. Distribution within the archipelago: T – Tristan
da Cunha Island, N – Nightingale Is., I – Inaccessible Is., S – Stoltenhoff Is., G – Gough Is., M – Middle (Alex) Is.
TAXON NAME
DISTRIBUTION
*Buellia acunhana (Nyl.) Zahlbr. - Wace & Dickson (1965: 353)
*Caloplaca austroatlantica Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 44)
T
Cladonia balfourii Cromb. - des Abbayes (1940: 4), Wace & Dickson (1965: 353)
C. capitellata (Tayl.) Bab. f. - des Abbayes (1940: 3), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. ceratophylla (Sw.) Spreng. - des Abbayes (1940: 3), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. coccifera Willd. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. coccifera var. aberrans des Abb. - des Abbayes (1940: 1)
C. didyma (Fèe) Vain. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. didyma var. vulcanica f. minor - des Abbayes (1940: 2)
C. fallax f. condensata - des Abbayes (1940: 1)
C. gracilis (L.) Willd. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. gracilis var. chordalis - des Abbayes (1940: 3)
C. chlorophaea (Flörke ex Sommerf.) Spreng. - des Abbayes (1940: 4 as C. pyxidata var. chlorophaea)
C. laevigata (Wain.) Gyeln. - Wace & Dickson (1965: 353 as Cladonia mitis), Jørgensen (1977: 11)
C. macilenta Nyl. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. macilenta var. styracella - des Abbayes (1940: 3)
C. mitis f. laevata - des Abbayes (1940: 1)
C. ochrochlora - des Abbayes (1940: 4), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. pityrea (Flk.) Fr. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. pycnoclada (Pers.) Nyl. - Jørgensen (1979: 2281); as Cladonia fallax - des Abbayes (1940: 1), Wace & Dickson
(1965: 353)
C. pyxidata (L.) Fr. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. pyxidata var. neglecta - des Abbayes (1940: 4)
C. scabriuscula (Del.) Sandst. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
C. squamosa Hoffm. - Christophersen (1934: 13), Wace & Dickson (1965: 353)
G
*Cresponea sorediata Elix, Øvstedal & Gremmen, sp. nov. - Elix, Øvstedal & Gremmen (2011: 134)
G
Dirinaria applanata (Fée) Awasthi - Jørgensen (1977: 11), Jørgensen (1979: 2281)
N,I,M
Erioderma groendalianum (Ach.) Wain. - Jørgensen (1977: 12), Jørgensen (1979: 2281)
I
*Gyalidea goughensis Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 44)
G
Heterodermia casarettiana (Mass.) Trevis. - Jørgensen (1977: 10 as Anaptychia casarettiana), Jørgensen (1979:
2281)
N
H. leucomela (L.) Poclt - Jørgensen (1977: 10 as Anaptychia leucomela), Jørgensen (1979: 2281)
N
H. speciosa (Wulf.) Trevis - Jørgensen (1977: 10 as Anaptychia speciosa), Jørgensen (1979: 2281)
I
Hypotrachyna bogotensis (Vain.) Hale - Elix & Gremmen (2002: 259)
G
H. endochlora (Leight.) Hale - Elix & Gremmen (2002: 260); as Parmelia endochlora - Jørgensen (1977: 15), Jørgensen
(1979: 2281)
G, N, I
H. gondylophora (Hale) Hale - Ryan et al. (2007: 59)
H. microblasta (Vain.) Hale - Elix & Gremmen (2002: 260); as Parmenia microblasta Wain. - Jørgensen (1977: 16),
Jørgensen (1979: 2281)
G, T, I
H. revoluta Flörke - as Parmelia revoluta - Wace & Dickson (1965: 353), Jørgensen (1977: 17), Jørgensen (1979: 2281)
I
Lecanora subfusca Ach. - Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
*Lepraria goughensis Elix & Øvstedal, sp.nov. - Elix, Øvstedal & Gremmen (2005: 274)
G

34
APPENDIX 7.1 – (continued)
TAXON NAME
DISTRIBUTION
Leptogium cf. azureum (Ach.) Mont. (Syn. L. tremelloides) - Jørgensen (1977: 12), Jørgensen (1979: 2281)
I
L. brebissonii Mont. - Jørgensen (1977: 13), Jørgensen (1979: 2281)
T,I
L. denticulatum auct. non. Nyl. - Jørgensen (1977: 13)
T,I
L. laceroides B. de Lesd. - Jørgensen (1977: 14), Jørgensen (1979: 2281)
I
*Massalongia griseolobulata Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 45)
G
Normandina pulchella (Borr.) Nyl. - Jørgensen (1979: 2281)
Parmelia cetrata Ach. Coll. - Christophersen (1934: 13), Wace & Dickson (1965: 353), Jørgensen (1977: 14),
Jørgensen (1979: 2281)
T,N,S,G
P. dilatata Wain. coll. - Jørgensen (1977: 15), Jørgensen (1979: 2281)
N
P. dissecta Nyl. - Jørgensen (1977: 15), Jørgensen (1979: 2281)
N,S
P. formosana Zahlbr. coll. - Jørgensen (1977: 16), Jørgensen (1979: 2281)
N
P. maura Pers. (Syn. P. reticulata) - Jørgensen (1977: 16), Jørgensen (1979: 2281)
T,N,I
P. microspora Müll. Arg. - Jørgensen (1977: 16), Jørgensen (1979: 2281)
T,N
P. reddenda Stirt. - Jørgensen (1977: 17), Jørgensen (1979: 2281)
S
**P. revolutella Nyl. - Wace & Dickson (1965: 353), Jørgensen (1977: 18), Jørgensen (1979: 2281)
T,S
P. rockii Zahlbr. - Jørgensen (1977: 18), Jørgensen (1979: 2281)
N
P. rudecta Ach. - Jørgensen (1977: 18), Jørgensen (1979: 2281)
N
P. saxatilis (L.) Ach. - Christophersen (1934: 13), Wace & Dickson (1965: 353)
G
P. sphaerosporella Müll. (syn. Ahtiana sphaerosporella) - Christophersen (1934: 13), Wace & Dickson (1965: 353)
G
Parmeliella nigrocincta (Mont.) Müll. Arg. - Jørgensen (1977: 18), Jørgensen (1979: 2281)
T
P. parvula P. M. Jørg. N. sp. - Jørgensen (1977: 19), Jørgensen (1979: 2281)
I
P. pycnophora (Nyl.) R. Sant. - Jørgensen (1977: 20), Jørgensen (1979: 2281)
T I
Parmelinopsis afrorevoluta (Krog & Swinsc.) Elix & Hale - Elix & Gremmen (2002: 260)
G
Parmotrema arnoldii (Du Rietz) Hale - Elix & Gremmen (2002: 261)
G
P. crinitum (Ach.) M. Choisy - Elix & Gremmen (2002: 261); as Parmelia crinita - Jørgensen (1977: 15), Jørgensen
(1979: 2281); as Parmelia proboscidea in Wace & Dickson (1965: 353)
G,T,N,S
P. gardneri (C. W. Dodge) Sérus. - Elix & Gremmen (2002: 261)
G
P. perforatum (Wulf.) xxx - Wace & Dickson (1965: 353)
P. perlatum (Huds.) Ach. - Wace & Dickson (1965: 353); as Parmelia perlata (Huds.) Ach. - Jørgensen (1977: 17),
Jørgensen (1979: 2281)
T,N,I
P. reticulatum (Taylor) M.Choisy - Elix & Gremmen (2002: 262 as Rimelia reticulata)
G
Peltigera dolichorhiza Nyl. - Jørgensen (1977: 20), Jørgensen (1979: 2281)
T,I
P. friesiorum Gyeln. - Jørgensen (1977: 20), Jørgensen (1979: 2281)
T
P. polydactyla (L.) Hoffm. - Wace & Dickson (1965: 354)
Physcia erosula Nyl. - Jørgensen (1977: 21), Jørgensen (1979: 2281)
I
P. stellaris Nyl. - Christophersen (1934: 13), Wace & Dickson (1965: 353)
G
P. tribacioides Nyl. (syn. P. sorediata) - Jørgensen (1977: 21), Jørgensen (1979: 2281)
Physciopsis adglutinata (Flk.) Choisy - Jørgensen (1977: 22), Jørgensen (1979: 2281)
N
Placopsis cribellans (Nyl.) M. Lamb - Lamb (1940: 1), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
T
P. fuscidula M. Lamb - Lamb (1940: 1), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
T
P. gelida (L.) Linds. - Lamb (1940: 2), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
T
P. parellina (Nyl.) M. Lamb - Lamb (1940: 3), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
P. parellina var. carnea (Räs.) M. Lamb - Lamb (1940: 3)
I
P. parellina var. rhodocarpa (Nyl.) M. Lamb - Lamb (1940: 3)
T
P. perrugosa (Nyl.) - Lamb (1940: 4), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
T

35
APPENDIX 7.1 – (continued)
TAXON NAME
DISTRIBUTION
P. rhodophalma (Müll. Arg.) Räs. - Lamb (1940: 4), Wace & Dickson (1965: 353), Jørgensen (1979: 2281)
T
Polychidium dendriscum (Nyl.) A. Henssen - Jørgensen (1977: 22), Jørgensen (1979: 2281)
T,I
Pseudocyphellaria aurata Vain. -Wace & Dickson (1965:353),Jørgensen (1977:22),Jørgensen
(1979:2281),Ryan(2007:59)
T,N,I
P. gilva (Ach.) Malme - Jørgensen (1977: 23), Jørgensen (1979: 2281)
T
P. intricata (Del.) Vain. (syn. P. thouarsii) - Wace & Dickson (1965: 354), Jørgensen (1977: 23), Jørgensen (1979:
2281)
T,I
Psoroma hypnorum (Vahl) S. F. Gray var. paleaceum (Fr.) Rostr. - Jørgensen (1977: 24), Jørgensen (1979: 2281)
T
Punctelia canaliculata (Lynge) Krog - Elix & Gremmen (2002: 262)
G
Pyxine cf. cocoës (Sw.) Nyl. - Jørgensen (1977: 24), Jørgensen (1979: 2281)
I
Ramalina celastri (Spreng.) Krog & Swinscow (syn. R. ecklonii) - Jørgensen (1977: 24), Jørgensen (1979: 2281)
N
*R. elegantula P. M. Jørg. - Jørgensen (1977: 25), Jørgensen (1979: 2281)
I
R. cf. laevigata Fr. - Jørgensen (1977: 26), Jørgensen (1979: 2281)
N,S
R. peruviana Ach. coll. - Jørgensen (1977: 26), Jørgensen (1979: 2281)
N
R. cf. linearis (Sw.) Ach. - Jørgensen (1977: 26), Jørgensen (1979: 2281)
T
R. intermedia Del. - Wace & Dickson (1965: 354)
I
R. scopulorum Ach. (Syn. R. siliquosa) - Christophersen (1934: 13), Wace & Dickson (1965: 354)
G
R. tayloriana Zahlbr. - Jørgensen (1977: 27), Jørgensen (1979: 2281)
N
R. yemenensis (Ach.) Nyl. - Wace & Dickson (1965: 354)
I
Stereocaulon antarcticum Vain. - Wace & Dickson (1965: 354)
S. atlanticum - Ryan et al. (2007: 59)
S. corticatulum Nyl. - Jørgensen (1977: 27), Jørgensen (1979: 2281)
T,I
S. glabrum (Müll. Arg.) Wain. - Jørgensen (1977: 28), Jørgensen (1979: 2281)
T
S. implexum Th. Fr. - Wace & Dickson (1965: 354), Jørgensen (1977: 28), Jørgensen (1979: 2281)
T
S. meyeri Stein - Jørgensen (1977: 29), Jørgensen (1979: 2281)
T,I
S. ramulosum (Sw.) Rausch. - Wace & Dickson (1965: 354 as S. mixtum)
S. cf. myriocarpum Th. Fr. - Jørgensen (1977: 29), Jørgensen (1979: 2281)
T
S. vesuvianum Pers. - Jørgensen (1979: 2281)
T
Sticta ambavillaria (Bory) Ach. - Wace & Dickson (1965: 354), Jørgensen (1977: 30), Jørgensen (1979: 2281)
T,I
S. fuliginosa Nyl. (Dicks.) Ach. - Christophersen (1934: 13), Wace & Dickson (1965: 354), Jørgensen (1977: 30),
Jørgensen (1979: 2281)
I,G
S. limbata (Sm.) Ach. - Jørgensen (1977: 30), Jørgensen (1979: 2281)
I
*S. tesselata Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 46)
G
*Szczawinskia phylicae Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 47)
T
Teloschistes flavicans (Ew.) Norm. - Wace & Dickson (1965: 354), Jørgensen (1977: 30), Jørgensen (1979: 2281), Ryan
et al. (2007: 59)
N,I
Tephromela atra - Ryan et al. (2007: 59)
*Tephromela rimosula Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 47)
T
T. lepabinum (Ach.) Ach. - Jørgensen (1979: 2281)
*T. tristanense Øvstedal sp. nov. - Øvstedal & Gremmen (2010: 48)
T
Usnea articulata Hoffm. - Wace & Dickson (1965: 354)
U. barbata (L.) Wigg. em. Mot. - Christophersen (1934: 13), Wace & Dickson (1965: 354)
G
U. ceratina Ach. - Jørgensen (1977: 31), Jørgensen (1979: 2281), Wace & Dickson (1965: 354 as U. plicata)
T,N
U. dasycera (Nyl.) Mot. - Jørgensen (1977: 32)
T,N,I
*U. nigropapillosa P. M. Jørg. N. sp. - Jørgensen (1977: 32), Jørgensen (1979: 2281)
N,S

36
APPENDIX 7.1 – (continued)
TAXON NAME
DISTRIBUTION
U. rubicunda Stirt.coll. - Jørgensen (1979: 2281), Wace & Dickson (1965: 354 as U.rubigena)
U. strigosa subsp. rubiginea (Michaux) I. Tav. - Jørgensen (1977: 34 as U. rubiginea)
N
*U. vermicularis P. M. Jørg. - Jørgensen (1977: 35), Jørgensen (1979: 2281)
I
Verrucaria durietzii I.M. Lamb - Ryan et al. (2007: 59)
APPENDIX 7.2 - List of 156 moss taxa reported from the Tristan da Cunha archipelago.
NOTE: * Endemic; ? Doubtful records. Distribution within the archipelago: T – Tristan da Cunha Island,
N – Nightingale Island, I – Inaccessible Island, G – Gough Island.
TAXON NAME
DISTRIBUTION
*Amblystegium patenti-flexuosum Dixon - Dixon (1960: 41)
I
*A. stricto-serpens Dixon - Dixon (1960: 40)
T
*Andreaea atlantica Dixon - Dixon (1960: 9)
T
A. grimmioides Dus. - Dixon (1960: 8)
T
A. nitida var. aquatica (R. Br. bis) W. Martin - Dixon (1960: 9 as Andreaea aquatica)
T
A. parallela C. M. - Dixon (1960: 9); Wace & Dickson (1965: 342)
A. regularis C. M. - Dixon (1960: 9)
T
A. rupestris Hedw. - Wace & Dickson (1965: 342 as A. loricata Dus.)
G
*A. squarrifolia Dixon - Dixon (1960: 10)
T
Androcryphia confluens - Bartram (1959: 210)
G
Anomobryum julaceum W. P. Schimper - Dixon (1960: 30 as A. filiforme)
T
*Bartramia inconspicua Mitt. - Dixon (1960: 7)
T
B.ithyphylla Brid. - Dixon (1960: 35 as B. stenobasis Card.) Ochyra (1999: 515)
T,G
*B. obscura Dixon - Dixon (1960: 35)
T
B. patens Brid. - Dixon (1960: 35)
T,I
B.robusta H. f. & W. - Dixon (1960: 7 as B. radicosa Mitt.)
T
Bazzania skottsbergii (St.) Fulford. - Bartram (1959: 210)
G
*Blindia brachystegia Dixon - Dixon (1960: 14)
T
*B. subcapillifolia Dixon - Dixon (1960: 14)
T
Brachymenium megalacrion (Schwägr.) Jaeg. - Wace & Dickson (1965: 344)
Brachythecium austroglareosum (Müll. Hal.) Kindb. - Ochyra (1999: 514); as Brachythecium subpilosum (H. f. & W.)
Jaeg. - Bartram (1959: 210), Dixon (1960: 43); Wace & Dickson (1965: 345 as Brachythecium pallidoflavens Card.)
T,G
Brachythecium subplicatum (Hampe) Jaeg. - Wace & Dickson (1965: 345)
G
Braunia humboldtii (Hook.) Hook. f. - Wace & Dickson (1965: 345 as Rhacocarpus humboldtii (Hook.) Lindb.)
G
? Breutelia dumosa Mitt. - Christophersen (1934: 10); Wace & Dickson (1965: 344)
G
B. integrifolia (Tayl.) Jaeg. - Dixon (1960: 37)
T
B. popinqua Kaal. - Dixon (1960: 37)
T,I
*B. tenuifolia (Mitt.) Par. - Dixon (1960: 37); Bartram (1959: 210)
T,I,G
*Bryum amplifolium Dixon - Dixon (1960: 31)
T
*B. cymbifoliellum Dixon - Dixon (1960: 32)
T
*B. flaccidifolium Dixon - Dixon (1960: 6)
T
? *B. fluitans Dixon - Dixon (1960: 33)
I

37
APPENDIX 7.2 – (continued)
TAXON NAME
DISTRIBUTION
B. laevigatum H. f. & W. - Dixon (1960: 33 as B. incurvifolium)
T
*B. subantarcticum Dixon - Dixon (1960: 33)
T,I
*B. subulinerve Card. - Dixon (1960: 33)
I,G
*B. tenellicaule Card. - Dixon (1960: 31); Bartram (1959: 210)
T,I,G
*B. tristaniense Dixon - Dixon (1960: 30)
T
? B. truncorum Brid. - Dixon (1960: 34)
T,I,N
? Campylium polygamum (Bry. Eur.) Bryhn - Dixon (1960: 42)
T
*Campylopus alienus Dixon - Dixon (1960: 19)
T,I,N
C. arcuatus Mitt. - Wace & Dickson (1965: 343)
T
C. pyriformis (Schultz) Brid. - Dixon (1960: 19 as C. calvatus; 20 as C. luscinialis)
T,I,N
C. incrassatus Müll. Hal. - Wace & Dickson (1965: 343 as C. alvarezianus Card.)
G
C. introflexus (Hedw.) Brid. - Dixon (1960: 19)
T,I,N
C. vesticaulis Mitt. (Syn. C. saddleanus) - Dixon (1960: 18); Bartram (1959: 209)
T,G,N
C. richardii Brid. - Wace & Dickson (1965: 343 as Thysanomitrium richardii Schwaegr.)
G
Catagonium nitidum (H. f. & W.) Broth. - Dixon (1960: 45)
T
Chorisodontium aciphyllum (Hook. f. & Wilson) Broth. - Dixon (1960: 18 as Dicranum aciphyllum H. f. & W.)
T,I
Chrysoblastella chilensis (Mont.) Reimers - Dixon (1960: 16 as Dichodontium opacifolium Dixon)
T
*Ceratodon plano-marginatus Dixon - Dixon (1960: 13)
N
C. purpureus (Hedw.) Brid. - Dixon (1960: 23 as Barbula validinervia C. M.)
T,N
Cratoneuron sp. - Dixon (1960: 42)
T
Cyclodictyon laete-virens (Hook. & Tayl.) Mitt. - Dixon (1960: 39)
T,I,G
*Daltonia tristaniensis Dixon - Dixon (1960: 39)
T,G
Dicranella fuegiana Card. & Broth - Dixon (1960: 15)
T
D. hookeri (C. M.) Card. (Syn. Anisothecium hookeri) - Dixon (1960: 15); Bartram (1959: 209)
T
D. vaginata (Hook.) Card. (Syn. Anisothecium vaginatum) - Dixon (1960: 15)
T
*Dicranodontium insularum Bartr. sp. nov. - Bartram (1959: 209)
G
*D. tristaniense Dixon & Thér. - Dixon (1960: 21); Bartram (1959: 209)
T
*Dicranoloma atlanticum Bartr. Sp. nov. - Bartram (1959: 209); Wace & Dickson (1965: 343)
D. hariotii (C. M.) Par. - Dixon (1960: 17); Bartram (1959: 209)
T,I,G
D. imponens (Mont.) Broth. - Dixon (1960: 17); Bartram (1959: 209)
T,I, G
*D. perdecurrens Dixon - Dixon (1960: 17); Bartram (1959: 209)
T
*Dicranoweisia falcifolia Dixon - Dixon (1960: 16)
T
Didymodon austroalpigena (C. M.) Broth. - Dixon (1960: 23)
T
Distichophyllum fasciculatum Mitt. - Dixon (1960: 39)
T
Ditrichum conicum (Mont.) Par. - Dixon (1960: 12)
T
D. flexifolium (Hook.) Hampe. - Dixon (1960: 13)
T,I,N
D. hyalinum (Mitt.) Par. - Dixon (1960: 12)
T
D. strictum (H. f. & W.) Hampe - Dixon (1960: 12)
T,I
*D. tenuinerve Dixon - Dixon (1960: 12)
T
Drepanocladus fluitans (Hedw.) Warnst. - Dixon (1960: 42 as Calliergon acuminatum Dixon)
T
Eustichia longirostris (Brid.) C. M. - Dixon (1960: 34)
T,G
Fissidens asplenioides Hedw. - Dixon (1960: 11)
T,I
*F. fluitans Dixon - Dixon (1960: 10)
T
F. leptochaete Dus. - Dixon (1950: 12)
I

38
APPENDIX 7.2 – (continued)
TAXON NAME
DISTRIBUTION
*Funaria euryloma Dixon - Dixon (1960: 28)
T,I
F. hygrometrica Hedw. - Wace & Dickson (1965: 344)
T
Grimmia kidderi James - Dixon (1960: 23 as Grimmia kerguelensis)
T,G
*G. stenobasis Dixon - Dixon (1960: 23)
T
Gymnostomum calcareum Nees & Hornsch. - Wace & Dickson (1965: 343)
T
Hennediella kunzeana (Müll. Hal.) Zander - Dixon (1960: 23 as Tortula kunzeana)
T
? Hygroamblystegium fuegianum (Besch.) Reimers, forma. - Dixon (1960: 41)
I
Hypnum cupressiforme Hedw. - Dixon (1960: 46); Bartram (1959: 210)
T,I,G
H.cupressiforme var. subjulaceum Mol. - Dixon (1960: 46); Bartram (1959: 210)
T,G
H. chrysogaster Müll. Hal. - Dixon (1960: 46 as Hypnum elatum Dixon)
T,I,N,G
*Isopterygium ambiguum Card. - Dixon (1960: 45)
T,N,G
I. brownii Card. - Wace & Dickson (1965: 345)
G
*I. tristaniense Dixon - Dixon (1960: 45)
T,N
Leptodontium interruptum (Mitt.) Broth. - Dixon (1960: 23)
T
Leptotheca gaudichaudii (Spreng.) Schwaegr. - Wace & Dickson (1965: 345)
G
? *Lepydoron alaris Dixon - Dixon (1960: 38)
T,G
Macromitrium sp. Brid. - Dixon (1960: 28)
*M. acutirameum Mitt. - Dixon (1960: 6)
T
*M. antarcticum C. H. Wright - Dixon (1960: 28)
T,I,N,G
M. fimbriatum Schwaegr. - Dixon (1960: 28)
T
Meiothecium urceolatum (Schwaegr.) Broth. - Wace & Dickson (1965: 345)
T
Neohodgsonia mirabilis H. Persson - Bartram (1959: 210)
G
*Oligotrichum tristaniense Dixon - Dixon (1960: 47)
T
Oncophorus fuegianus Card. - Christopherson (1934: 9)
G
Orthostichopsis subimbricata (Hampe) Broth. - Wace & Dickson (1965: 345)
T
Orthotheciella varia (Hedw.) Ochyra - Dixon (1960: 40 as Amblystegium excurrens Broth. & Card.)
T
? Pleuropus bonplandi (Hook.) Broth. - Dixon (1960: 43)
T,I
*Philonotis capillata Mitt. - Dixon (1960: 36); Bartram (1959: 210)
T,G
P. scabrifolia (H. f. & W.) Mitt. - Dixon (1960: 36)
T
P. tenuis (Tayl.) Jaeg. - Dixon (1960: 36)
T,I,G
P. vagans (H. & W.) Mitt. - Christophersen (1934: 10); Dixon (1960: 36)
T,G
Phyllogonium fulgens (Sw.) Brid. - Wace & Dickson (1965: 345)
G
P. viscosum (Beauv.) Mont. - Bartram (1950: 210)
T,G
*Physcomitrium aubertii Besch. - Dixon (1960: 2)
T,I
Pohlia elongata Hedw. - Dixon (1960: 29)
T
*Pohlia excurrens (Dixon) E.B. Bartram - Christophersen (1934: 9 as Webera excurrens Dixon); Dixon (1960: 30)
T,I,G
P. nutans (Hedw.) Lindb. - Dixon (1960: 29)
T,G
P. wahlenbergii (Web. & Mohr) Andrews - Christophersen (1934: 10 as Mniobryum albicans (Wahlenb.) Limpr.);
Dixon (1960: 30 as Mniobryum wahlenbergii)
T,G
Polytrichadelphus magellanicus (Hedw.) Mitt. - Dixon (1960: 49); Bartram (1959: 210)
T,I,G
? Polytrichum gracile Sm. - Wace & Dickson (1965: 345)
G
P. juniperinum Hedw. - Dixon (1960: 49)
T,I,N,G
P. piliferum - Ryan et al. (2007: 57)
*Porotrichum atlanticum Dixon - Dixon (1960: 7)
T

39
APPENDIX 7.2 – (continued)
TAXON NAME
DISTRIBUTION
? Pseudoscleropodium purum (Limpr.) Fleisch. - Dickson (1967)
T
Psilopilum antarcticum (C. Muell) Par. - Wace & Dickson (1965: 345)
T
*P. laxifolium Dixon - Dixon (1960: 48)
T,I
*P. tristaniense Dixon - Dixon (1960: 48)
T
Ptychomnion densifolium (Brid.) Jaeg. - Dixon (1960: 38); Bartram (1959: 210)
T,I,G
Pyrrhobryum spiniforme (Hedw.) Mitt. - Dixon (1960: 34 as Rhizogonium spiniforme)
T,N
Racomitrium Brid. - Dixon (1960: 24 as Rhacomitrium)
R. crispulum (H. f. & W.) H. f. & W. - Dixon (1960: 24; 25 as R. heterostichoides Card.)
T,I,G
*R. decurrens Dixon - Dixon (1960: 26)
T
*R. gracillimum Dixon - Dixon (1960: 26)
T
R. laevigatum A. Jae. - Dixon (1960: 26 as R. breutelioides Dixon); Wace & Dickson (1965: 344 as Racomitrium
loriforme Dus.)
T,G
R. lamprocarpum (Müll. Hal.) Jaeg. - Dixon (1960: 25 as R. subnigritum); Ochyra (1999: 515)
T,G
R. lanuginosum (Hedw.) Brid. - Dixon (1960: 27); Bartram (1959: 209); Ryan et al. (2007: 57)
T,I,G
R. nigritum (C. M.) Jaeg. - Dixon (1960: 25)
T
? R. symphyodontum (C. Muell) Jaeg. - Wace & Dickson (1965: 344)
G
Rhizogonium spiniforme (Hedw.) Brunch. - Bartram (1959: 210)
T,N,G
*Rhynchostegium irriguum Dixon - Dixon (1960: 44)
T
*R. isopterygioides Card. - Dixon (1960: 44); Bartram (1959: 210)
T,I,N,G
? *Rigodium crassicostatum (Dix.) Bartr. - Dixon (1960: 43); Wace & Dickson (1965: 345)
T
Sanionia uncinata (Hedw.) Loeske - Dixon (1960: 41 as Drepanocladus uncinatus (Hedw.) Warnst.)
T
*Schlotheimia atlantica Dixon - Dixon (1960: 28)
T
Sematophyllum crassiusculum (Brid.) Broth. - Dixon (1960: 44)
T,I,N
Sphagnum fimbriatum Wils. - Bartram (1959: 208); Christophersen (1934: 10)
G
S. magellanicum Brid. - Bartram (1959: 208); Wace & Dickson (1965: 342)
G
S.recurvum Beauv. - Dixon (1960: 8); Bartram (1959: 208)
T,G,I
S. violascens Müll. Hal. - as Sphagnum scotiae Card. - Bartram (1959: 208), Christophersen (1934: 10)
G
Syrrhopodon gaudichaudii Mont. - Dixon (1960: 22 as S. atlanticus Dixon)
T,N,G
Thuidium alvarezianum Card. - Wace & Dickson (1965: 345)
G
T.furfurosum (H. f. & W.) Reich. - as Thuidium curvatum Mitt. - Dixon (1960: 40) and Bartram (1959: 209)
T,I,N,G
Tortula kunzeana (C. M.) Mitt. - Dixon (1960: 23)
T
T. muralis - Ryan et al. (2007: 57)
*Trematodon intermixtus Card. - Dixon (1960: 15)
T,I
Trichostomum sp. - Dixon (1960: 22)
T
T. aequatoriale Spr. (Syn. T. quitense Hampe) - Dixon (1960: 22)
T
? Weisia sp. - Dixon (1960: 22)
T
*Zygodon insularum Dixon - Dixon (1960: 27)
T