An open access copy of this article is available from the publishers website. Fine resolution pollen analysis shows that the late-glacial (c. 13 000-10 700 B.P.) vegetation of the Ohakune-Horopito area was dominated by Prumnopitys taxifolia, indicating a cooler and probably drier climate than the present. Around 10 700 B.P., Dacrydium cupressinum replaced Prumnopitys taxifolia as the forest dominant, and tree ferns and hardwood trees expanded, suggesting a change to warmer or wetter conditions. Around 5800-6300 B.P., Dacrydium cupressinum and tree ferns declined, Prumnopitys taxifolia regained some of its former dominance, and hardwood species continued to expand, suggesting a change to more variable conditions. Immediately following the Taupo Tephra eruption of 1718 B.P., Libocedrus bidwillii expanded at Gibsons' Swamp. The eruption may have facilitated a regional expansion of this species which was apparently already underway as a result of a climate change to stormier and cooler conditions prior to the eruption. Extensive logging for podocarps in Ohakune-Horopito after AD 1850 resulted in an increase in the abundance of Weinmannia racemosa.
We review the biology and ecology of Metrosideros excelsa (Myrtaceae), an endemic angiosperm evergreen tree. Metrosideros excelsa belongs to a conspicuous and widely distributed Pacific Basin genus, with centres of diversity in both New Zealand and New Caledonia. Metrosideros excelsa is an iconic tree species that forms a significant component of northern New Zealand's exposed coastal headland and cliff vegetation. Where conditions are more favourable, M. excelsa forms tall coastal forest, ranging from simple young high-density stands to diverse mature forest. Inland, M. excelsa stands are confined to the margins of lakes and rivers on the Central Volcanic Plateau, where some may originate from early Māori plantings. Metrosideros excelsa is reliant on stochastic disturbance events (e.g. landslides, volcanic eruptions) to create open sites necessary for regeneration. Mass flowering (December–January), followed by abundant production of wind-dispersed seed maximises chance colonisation of such sites. Since human settlement in New Zealand, the distribution of M. excelsa forest has declined by c. 90% and the southern limit of the species has retreated north. Natural regeneration on the mainland is limited by the infrequency of large-scale disturbances and increased anthropogenic and herbivore pressures. Consequently, M. excelsa forest has become rare and localised on the mainland; monitoring and active management are fundamental to the species' long-term conservation.
Tephra eruptions have significant long-lasting impacts on vegetation, and potentially explain extant vegetation patterns in volcanic landscapes. We quantified the effects of the AD 1655 Burrell Lapilli deposit, Mt Taranaki, on treeline vegetation. Where lapilli depth was 25–40 cm, a succession close to primary was initiated. Where lapilli depth was 5–25 cm, the canopy was opened, but some vegetation survived. Total tree basal area remains lower in affected vegetation (158 cf. 206 m2 ha−1), whereas total tree density is higher where a moderate disturbance stimulated regeneration (8433 cf. 6656 stems ha−1). Griselinia littoralis and Podocarpus cunninghamii dominate treeline vegetation (c. 51 and 39 m2 ha−1, respectively) within the lapilli distribution. Where disturbance was moderate, a cohort of Libocedrus bidwillii was also initiated. Weinmannia racemosa is absent from treeline vegetation within the lapilli distribution, despite being a dominant component elsewhere (basal area 48 m2 ha−1). Compositional patterns result from interspecific differences in morphology and resilience, as well as light, substrate and temperature tolerance. Light-demanding, cold-tolerant taxa were able to take advantage of the newly created open sites, whereas shade-tolerant, less hardy species lost their competitive advantage at the treeline elevation. The successional trajectory of the treeline vegetation has been set back and altered, and there is no evidence of convergence.
An open access copy of this article is available from the publishers website. Fine resolution pollen analysis of a core from Erua Swamp shows that prior to the Taupo eruption of c. 17 l 8 B.P., the site bore a dryland vegetation type on river flats. Patchy Nothofagus/Phyllocladus forest on the flats was destroyed by the eruption and replaced by Gleichenia-restionad swamp vegetation with abundant Halocarpus. Regional forest during the period from after the eruption to c. 650-560 B.P. was mixed podocarp, dominated by Dacrydium cupressinum and Prumnopitys taxifolia. A period of widespread and sustained anthropogenic destruction by fire of forest commenced c. 650-560 B.P.
An open access copy of this article is available from the publishers website. Documented chromosome numbers are reported for 187 taxa (170 species, 9 subspecies, 8 varieties), 5 hybrids (four putative, one artificial), and 18 of uncertain rank from 50 families (84 genera; 2 lycophyte, 11 pterophyte and 71 anthophyte). Of these, 189 counts are new for the New Zealand flora (167 of these are from named taxa). Many of the counts reported are from more poorly investigated families (e.g., Cyperaceae, Lycopodiaceae, Potamogetonaceae) and genera (e.g., Desmoschoenus, Freycinetia, Lycopodiella, Lycopodium, Potamogeton, Schoenus) indigenous to New Zealand, or from nationally uncommon and/or threatened taxa (e.g., Eleocharis neozelandica, Hebe societatis, Myriophyllum robustum, and Pittosporum dallii) and/or newly described plants (e.g., Gingidia grisea, Olearia adenocarpa), while three counts are from naturalised species (Alternanthera sessilis, Nephrolepis cordifolia, and Senecio skirrhodon), and one from a cultivated plant of Metrosideros nervulosa. In the majority of genera the numbers follow established patterns. Counts have now been obtained for all known New Zealand representatives of the Alseuosmiaceae, Chloranthaceae, Dryopteridaceae, Elatinaceae, Euphorbiaceae, Geraniaceae, Hydatellaceae, Lauraceae, Linaceae, Rubiaceae, Scrophulariaceae, Nephrolepidaceae, Nyctaginaceae, Pandanaceae, Polypodiaceae, Sapotaceae, and Thelypteridaceae.
An open access copy of this article is available from the publishers website. When nodal explants from tips of horizontal branches of seedling Agathis australis (Araucariaceae) are cultured in vitro, the distal 3 mm of internode progresses through a series of morphological and anatomical changes, and ultimately detaches. Changes include: desiccation; regional chlorosis; internode swelling associated with proliferation and radial expansion of cortical parenchyma; interruption of vascular contiguity by invading vascular parenchyma; necrosis and separation. Explants from material older than one growth flush, and those from orthotropic axes, do not exhibit this syndrome. Second-generation explants show internode abscission, regardless of age of parent material. The technique may be a useful experimental system for studying branch cladoptosis in woody species.
Distinctly different vegetation communities occur on the acidic soils that form beneath Agathis australis compared with adjacent lower acidity soils developed under other canopy species. Globally, species that occur on acidic soils typically have inherently low activity levels of the enzyme nitrate reductase, as they predominantly use NH4-N rather than NO3-N. Using in vivo assays, I examined the nitrate reductase activity in the leaves and roots of eight plant species of varying spatial association with A. australis. Seedlings of each species were grown together in a shade house in potting soils containing saturating levels of nitrate. I did not find evidence to suggest that the species common beneath A. australis, including Leucopogon fasciculatus in the Ericaceae, had lower abilities to metabolize nitrate when available than the understorey species dominant in surrounding forest with A. australis absent. The results suggest that the reduced abundance of A. australis-associated species within the surrounding forest is unlikely to be related to their ability to use NO3-N.
An open access copy of this article is available from the publishers website. A total of 75 taxa (including 1 hybrid) are reported as new to the flora of the Norfolk Island group, in the south-west Pacific Ocean. Of these 1 is endemic (Achyranthes margaretarum), and 10 (2 pteridophytes, 8 anthophytes) taxa are considered indigenous and appear to represent either new natural long-distance colonisations of Norfolk Island group from Australia and New Zealand or are new identifications of indigenous taxa either treated under other indigenous names or as naturalised in the Norfolk Flora. The remaining 64 taxa are considered naturalisations from resident gardens, or recent arrivals via human traffic from Australia or New Zealand. Aside from these records we discuss and update information on a further 27 taxa either covered by the last Norfolk Island flora treatment, or noted in subsequent works. A new species, Geranium gardneri, is described and treated as indigenous to Australia and naturalised in Norfolk I. and New Zealand. Nephrolepis flexuosa is reinstated for the non-tuberous, high-polyploid fern previously included within a broad circumscription of N. cordifolia, and which is indigenous at least to Norfolk L, Raoul L, Lord Howe L, New Zealand, and Fiji. The new combination Boehmeria australis subsp. dealbata is made for the Raoul I. (Kermadec Islands group) endemic, and Elymus multiflorus subsp. kingianus for the Norfolk and Lord Howe Island wheatgrass. The New Zealand Cordyline kaspar and Raoul I. Rhopalostylis cheesemanii are relegated to synonymy within the Norfolk I. Cordyline obtecta and Rhopalostylis baueri, respectively, which are now no longer considered endemic. Dianella intermedia and Pennantia endlichen are treated as endemic to Norfolk I. and Senecio australis as indigenous. Two species, Ipomoea cairica and Oxalis exilis, previously treated as naturalised are recognised as indigenous, while Homalanthus populifolius is now considered naturalised and so is excluded from the indigenous flora. A new treatment for Norfolk I. Oxalis Sect. Corniculatae is offered, and three of the four taxa reported from the island group but treated by the current flora as part of O. corniculata sens. lat. are recognised at species rank. Of these we consider only one, O. exilis, to be indigenous, and treat O. choonodes and O. radicosa as probably naturalised. We also report the first naturalised occurrence of O. corniculata sens. str. from the island group and exclude O. perennans from the flora. Isolepis cernua var. setiformis is recognised for the Norfolk I. Isolepis previously treated as probably endemic and unnamed.
An open access copy of this article is available from the publishers website. Two polymorphic members of the Adiantum hispidulum Swartz complex, A. hispidulum sensu stricto and A. pubescens Schkuhr, have been critically studied on a morphological basis, utilising frond and hair forms, pinnule shape and size, soral features, number of sporangia per sorus, sporangial size, annulus position and number of indurated cells, spore shape and size, rhizome and stipe paleae. Separation of the two taxa is traditional- ly based on frond form (A. hispidulum being described as pinnate and A. pubescens as pedate), and indumentum characteristics (A. hispidulum having medium to short stiff hairs, A. pubescens having long lax hairs). This study shows that only those characters associated with the pinnule hairs can be used to consistently separate the two taxa (A. hispidulum has short (63�815 |im), stiff, often pigmented hairs with enlarged basal cells, while A. pubescens has long (251-1003 \im), soft, pale hairs with narrow basal cells). However, even these characters showed a high degree of variability. Adiantum pubescens is given varietal status as A. hispidulum var pubescens.
Ten pollen records from the Cobb Valley and adjacent areas in North-West Nelson are described. Collectively they provide a vegetation record extending from the Last Glacial Maximum to the present day. During the Last Glacial Maximum the uplands of North-West Nelson were glaciated. By about 17 000 radiocarbon years BP ice had retreated some distance up the Cobb River valley and a podocarp heath and tussockland vegetation covered non-glaciated areas. By 14 000 radiocarbon years BP, the valley floor and adjacent lower ridges were occupied by montane podocarp forest dominated by Phyllocladus and Halocarpus. Beech forest expanded into some sites as early as 13 000 yr BP but the modem beech cover was not established until the Holocene. Forest cover has fluctuated in response to disturbance over the Holocene, but the most significant recent change, which is related to clearing for pastoralism in the last two centuries, has had surprisingly little impact on the pollen records.
An open access copy of this article is available from the publishers website. Anthocyanin pigmentation is a prominent feature in the adventitious roots of Metrosideros excelsa. We describe the histological distributions and chemical nature of anthocyanins in these roots, and quantify their antioxidant activity. Anthocyanins were present in one or more cell layers of the root cap, epidermis, hypodermis, and cortex. A narrow band immediately behind the root apex was usually anthocyanin free. Photosensitivity of anthocyanin biosynthesis was evident both for adventitious roots and for plagiotropic roots exposed at the soil surface. The anthocyanins were cyanidin- and delphinidin-based. Methanolic extracts of the roots did not show a direct relationship between anthocyanin concentration and antioxidant activity. The possible function of anthocyanins in these roots is unknown.
An ability to tolerate salinity can be critical for plants growing in coastal environments. We hypothesised that differences in salinity tolerance might explain variations in vigour and distribution patterns among four iceplant taxa on the Wellington coast. Growth rates, biomass allocation and quantum efficiencies of photosystem II were compared under three salinity levels for Carpobrotus edulis, Carpobrotus chilensis, Disphyma australe and a hybrid presumed to be C. edulis × D. australe. Carpobrotus edulis was significantly less tolerant of seawater-strength salinity relative to the other taxa. The data did not support a correlation between salinity tolerance and competitiveness in these iceplants. Chlorophyll a fluorescence measurements revealed no permanent adverse impacts on photosynthetic efficiency resulting from long-term exposure to salinity. However, salt-induced growth differences observed among iceplant taxa are probably due to the changes in their photosynthetic capacities.
An open access copy of this article is available from the publishers website. From a study of species of Campanella P. Hennings collected in New Zealand, descriptions are given of three new species, C. fimbriata, C. rubescens, and C. vinosolivida. Two species previously described from New Zealand as Resupinatus tristis and R. dorotheae have been reexamined and combined together as C. tristis comb, nov.
An open access copy of this article is available from the publishers website. Records of some 600 species of agarics and boleti published for New Zealand prior to 1986 are listed, including bibliography, synonymy, and reference to illustrations.
An open access copy of this article is available from the publishers website. The "transient' and "persistent' components of the soil seed bank beneath a kauri forest remnant are described, recent seed rain (collected in trays over a two year period being distinguished from dormant viable seed with longevity >2 years (soil beneath trays). A total of 46 vascular plant species was recorded. Trays are dominated by 4 woody, native species, Kunzea ericoides, Coprosma arborea, Myrsine australis and Carpodetus serratus. Sub-tray samples show an accumulation of seeds from light-demanding weedy species, including many adventives, eg Solanum mauritianum, Phytolacca octandra and Cirsium vulgare. In addition, seeds of 2 woody, native species, Cordyline australis and Geniostoma rupestre, are abundant. Detrended correspondence analysis shows clear differences between floristic composition of trays and sub-trays, and between on-site vegetation and components of the soil seed bank. differences explained in terms of seed longevity, seed accumulation rates, suitability of site conditions for growth of individual species, and the role of seed dispersal agents, especially birds.
An open access copy of this article is available from the publishers website. Twenty five plots of mature kauri Agathis australis (D. Don) Lindl., covering the range of the species in northern New Zealand, were sampled for density, basal area, and species composition using a modified point-centered quarter technique. Two increment cores were taken from at least ten trees at most sites, and used to estimate tree ages and growth rates. The density of kauri stems ^ 10 cm d.b.h. ranged from 17 to 416 ha~', and the basal area from 23 to 127 m2 ha~' in the 25 stands. Diameter distributions ranged from highly skewed and unimodal to flat and multi- modal, with all size classes represented in most plots. Combined frequency distributions suggest that two or three kauri generations (cohorts) may be present on many sites. There is only a weak relationship between age and diameter; individuals in the same 10 cm diameter class may vary in age by 300 years, and the largest individual on the site is often not the oldest. Mean annual diameter increments range from 0.15 to 0.46 cm yr~'on different sites with an overall average of 0.23 cm yr~>, equivalent to 8.7 annual rings per cm of core, about half the com- monly quoted figure for growth rate. Periodic mean annual increment and mean annual increment curves are presented. It is concluded that the "normally attainable age" is >600 years. Individuals >2 m d.b.h. probably often exceed 1000 years, but there is no reliable evidence for trees >2000 years in age. individuals in the same 10 cm diameter class may vary in age by 300 yr, and the largest individual on the site is often not the oldest. Mean annual diameter increments range from 0.15-0.46 cm yr-1 on different sites with an overall average of 0.23 cm yr-1, equivalent to 8.7 annual rings per cm of core. The "normally attainable age' is >600 yr. Individuals >2 m dbh probably often exceed 1000 yr, but there is no reliable evidence for trees >2000 yr in age.
An open access copy of this article is available from the publishers website. Simple dendrometer bands were used to measure the radial increment of kauri (Agathis australis Salisb.) at 3 sites to the south and east of Auckland during the 1980-81 growing season. Diameter increment cores taken from some of the trees at the beginning and end of the study showed that the radial expansion measured by the bands correlated significantly (P<0.001) with the width of the annual ring formed over the same period. A reduction in tree growth rate during summer drought was recorded at 2 mid-altitude sites, but not near the altitudinal limit of kauri. These growth patterns were attributed to the different soil moisture conditions at the different sites.
The ecology of Alseuosmia quercifolia, a small endemic shrub, was investigated, focussing on its habitat requirements, population dynamics, phenology and reproductive biology, and conservation status. This species occurs most commonly in lowland native forests of the Waikato region of the North Island (north of latitude 38°05'S), but is also found in scattered populations to North Cape. In the Waikato region it typically occupies shady, well-drained, south or south-east facing lower slopes of hills and ranges at altitudes below 400 m. Population structures show considerable variation amongst seven study sites in the Waikato region, with disjunct size classes a reflection of the presence and abundance of introduced browsing mammals. It is a relatively short-lived (less than 50 years), slow-growing species with a fleshy fruit adapted to bird dispersal, but seed dispersal now appears to be primarily by gravity. Flowering occurs early in spring and is synchronous at both individual and population levels, occurring over a 5-week period, with peak flowering during the second and third weeks. While all populations set seed, reproductive output can be negatively affected by persistent browse and by rain during peak flowering. This species is vulnerable because it is highly palatable to introduced mammals and all plants in a population are within browse height. It has relatively narrow habitat specificity, localised distribution, and limited potential to extend its range. We suggest it fulfils the requirements of the category "declining", using the most recent classification of threatened and uncommon plants of New Zealand. The final, definitive version of this article has been published in the Journal, New Zealand Journal of Botany, 40(1), (2002), (c) Royal Society of New Zealand at the Royal Society of New Zealand Journals Online webpage.
In a recent revision of generic circumscriptions in the Lindsaeaceae ferns, three of the four New Caledonian species previously placed in Sphenomeris were transferred to Odontosoria. Using phylogenetic analyses of chloroplast DNA sequences, we show that the fourth species, Sphenomeris alutacea (Mett.) Copel., also fits within this expanded Odontosoria. Accordingly, we provide a new combination, Odontosoria alutacea (Mett.) Perrie & L.D. Sheph.
An open access copy of this article is available from the publishers website. Evidence is presented that the growth rings in the wood of fast growing tawa are annual. Diameter growth rates of tawa are variable but usually \-A mmyr1 in trees >20 cm diameter at 1.4 m height. Tawa probably has maximum longevity in the range 300-400 years. It shows unexplained biennial fluctuations in diameter increment, a feature shared with several New Zealand tree species.
An open access copy of this article is available from the publishers website. Anthocyanin pigments must reside in the uppermost tissues of a leaf if they are to be effective as UV-B filters. However, in our survey of leaves and phylloclades from 25 native New Zealand plants, only four species held anthocyanins in the upper epidermis and/or hypodermis. For 18 species, anthocyanins were located in vacuoles of the palisade and/or spongy mesophyll, the same tissues that are potentially susceptible to UV-B-induced photoinhibition. Leaf pigmentation patterns varied among species and were correlated to the histological distributions of anthocyanins. Most species held cyanidin-derived pigments. UV-B filtration cannot be regarded as a unified theory for anthocyanin function in leaves.
An experiment was conducted over two years to investigate the effect of Coriaria arborea, a native nitrogen-fixing shrub, on soil seed banks at sites representing a post-volcanic successional sequence on Mt Tarawera, New Zealand. The sites ranged from bare volcanic ash and lapilli substrate, through low-growing pre-Coriaria vegetation, to dense stands of Coriaria scrub. Soils (to a depth of 50 mm) under recently established Coriaria and older stands had more seedlings (1096 and 1585 seedlings 0.4 m-2, respectively) and species (37 and 45 species 0.4 m-2, respectively) emerge than where there was no Coriaria (243-320 seedlings 0.4 m-2, 14-25 species 0.4 m-2) and were the only soils with Coriaria seedlings. In total, 3488 seedlings representing 63 taxa were recorded. Seeds were still germinating after 24 months but rates declined markedly in the second year. For example, Coriaria reached a germination peak at 8 weeks but continued to germinate sporadically over the 2-year period. Tree species present in young forest within 0.5 km of the sites were absent. Establishment of Coriaria greatly accelerated an underlying trend of gradually increasing abundance and diversity of seeds in the soil with vegetation age. Adventive, wind-dispersed, and annual species were over-represented in the seed banks compared with the regional evergreen forest-dominated flora. These proportions are expected to decline as succession to forest gradually occurs. The final, definitive version of this article has been published in the Journal, New Zealand Journal of Botany, 40(4), (2002), (c) Royal Society of New Zealand at the Royal Society of New Zealand Journals Online webpage.
An open access copy of this article is available from the publishers website. Morphometric parameters that have been used previously to define divaricates are not useful for the genus Sophora. In measurements of forest-grown material, only node-angles effectively distinguished between the arborescent S. tetraptera and the divaricating species S. prostrata and S. microphylla. We examined the developmental basis for the generation of divaricating architecture in Sophora species by following growth of potted material over one year. The divaricating form was characterised by a twice-yearly production of new branches; sylleptic outgrowth in the spring, and proleptic outgrowth towards late summer. Branches arose predominantly from the proximal node. By contrast, the arborescent species had only a single growth period, and proleptic branches were produced from more distal nodes. In all three species, growth was most extensive in the uppermost regions of the canopy. Developmental processes may be better descriptors of divarication than shoot dimensions.
An open access copy of this article is available from the publishers website. Juvenile Pennantia corymbosa plants are divaricate in form. They display periodic growth patterns along axes; there are stem sections with long internodes, stem angles which deviate from 180�, and expanded lateral shoots, between which are stem sections with short internodes which lack lateral shoots and stem angles. There is a strong positional association between long internodes, stem angles, and lateral outgrowth. Plants have three shoot types - short shoots, non-sylleptic long shoots, and sylleptic long shoots - that differ in parental control of elongation. The ratios of leaf: total dry-weight biomass of juvenile P. corymbosa branches are similar to ratios from North American deciduous woody shrubs but lower than ratios from evergreen shrubs. Juvenile P. corymbosa plants display features such as phenotypic plasticity, a diversity of shoot types, and wide branch angles which may enhance light capture. However, the costs for light capture associated with a low contribution of biomass to foliage may be high.
Muehlenbeckia astonii Petrie is a compact, divaricating shrub. It produces both orthotopic and plagiotropic shoots but after a period of time the orthotopic shoots revert to a plagiotropic form. Orthotropic shoots differ from plagiotropic ones in that the internodes are longer, the shoots more erect and much straighter for the first 10-15 intemodes. A clonal population of two-year-old cuttings, taken from a female plant, was grown outdoors in pots. Those cuttings supplied with a balanced nutrient solution were more vigorous and produced more second-order orthotropic shoots than those not provided with nutrient. However, nutrient level did not affect the ultimate divaricating nature of the shoots. The vigour of the shoots varied. Generally, a shoot grew vigorously for the first season producing many other shoots of higher orders; then extension of the second-order axis ceased and further growth was restricted to the higher-order laterals. Most of the growth was carried out by shoots initiated in the current growing season. To a large extent the number and vigour of the orthotropic shoots determined the overall form of the plants. These shoots sometimes arose below or close to ground level but often in older plants also developed as laterals on second- or third-order shoots some distance above the ground. Plagiotropic shoots did not increase the overall height of the shrub to any great extent, but orthotropic ones were important in that they placed shoots at a higher elevation and thus increased the volume of space occupied by the plant.
An open access copy of this article is available from the publishers website. At species level, the three taxa currently recognised in the genus Rhopalostylis (Arecaceae) are: R. baueri of Norfolk Island, R. cheesemanii from the Kermadec Islands, and R. sapida (nikau) from New Zealand and the Chatham Islands, but this classification has not been universally accepted. Even within the New Zealand botanical region, adults and seedlings of the Chatham Islands variant differ morphologically from R. sapida in mainland New Zealand. However, juveniles of all entities are less easily distinguished, leading to concerns that this may become a problem for conservation in New Zealand. The indumentum on petioles of juvenile and adult specimens of Rhopalostylis from mainland New Zealand, Chatham Islands, Kermadec Islands, and Norfolk Island, and one specimen of Hedyscepe canterburyana from Lord Howe Island, was examined for characters that could distinguish between them. Hedyscepe scales were distinctive, but in Rhopalostylis taxa the scale morphology was too variable to be useful for distinguishing between juveniles. However, scale density and, to a lesser extent, scale-base maximum height have been identified as potentially useful characters for distinguishing the mainland Rhopalostylis plants from those of the Chatham Islands and other islands. Assessment of scale density in particular could be a practical, inexpensive, and reasonably reliable method for identification of juvenile plants in restoration projects.
An open access copy of this article is available from the publishers website. Linear discriminant function analysis (LDF) is assessed as a method of interpreting fossil pollen assemblages from Mt Hauhungatahi, Tongariro National Park, and Ohakune-Horopito, central North Island, New Zealand. Pollen types selected by stepwise discriminant analysis were used in LDF to predict the vegetation type (forest, dense scrub, open fernland, or open tussockland) and canopy type (closed or open) represented by fossil pollen assemblages from an array of sites. Chisquare Goodness-of-fit tests were used to test prediction made by LDF against the vegetation type suggested by the common "standard" method of assessment of the fossil pollen spectra, which is carried out by visual inspection of stratigraphic pollen diagrams. Some sites showed highly significant differences, with many samples obviously misclassified by LDF, especially those from montane forest vegetation. This misclassification occurred mainly because the montane forest samples were so different from the remainder that they were excluded from the prediction set, so that the pollen types most likely to be predictors were not employed. Overall, however, more sites showed no significant differences. The LDF method is confirmatory rather than providing a clear improvement, and its validity will depend strongly on the correct choice of discriminators.
An open access copy of this article is available from the publishers website. Meiotic chromosome counts of n = 9 (2n = 9) I have been determined from wild plants of Atriplelx (subgenus Teleophyton) billardierei gathered in New Zealand and on Chatham Island. Atriplex billardierei is an endangered species within New Zealand but remains abundant on Chatham Island.
An open access copy of this article is available from the publishers website. A 2.34 m sediment profile from the base of the crater of Mt St John volcano (a small basaltic cone on Auckland Isthmus) provides a partial environmental record of the Late Quaternary. The record highlights potential age control problems with sediment cores taken directly from archaeological sites. Two distal tephras were recorded: 9.5 ka Rotoma and 7 ka Tuhua. A date of 16 309 �90 14C yr BP from the basal scoria of the profile provides a minimum date for the eruption of Mt St John. Pollen was present only in the upper 0.33 m of the profile, in a layer of peat and soil which caps highly weathered silts and clays eroded from the crater walls. In early Polynesian times (most likely after c. 800 14C yr BP), vegetation of the crater swamp was dominated by Cyperaceae sedges and Paesia ground fern. Dacrycarpus trees were also present. Podocarp-hardwood forest, dominated by Metrosideros, grew on the rim and inner slopes of the crater. Elaeocarpus, Griselinia, and Cyathea were also present. A decline in Dacrycarpus pollen and an accelerated erosion rate mark Polynesian forest clearance within the crater. Typha became a major component of the swamp vegetation during the Late Polynesian-European era.
An open access copy of this article is available from the publishers website. Sporocarps, megaspores, and micro- spores of Azolla filiculoides are described from fresh fertile material from the South Island of New Zealand. Size estimates are given along with light and scanning electron microscope photographs. A brief discussion of spore morphology, perine substructure, and leaf trichomes is given with regard to the taxonomy of A. filiculoides and A. rubra. Differences between these taxa with regard to sporoderm substructure and the presence of filaments on the collar of the megaspore support their separation but may be considered insufficient to justify maintaining taxonomic separation beyond varietal status for rubra.
An open access copy of this article is available from the publishers website. One hundred and eight vegetation plots were measured along six transects, running from estuarine mudflats to freshwater swamp in Whangapoua Estuary. These were analysed to define the patterns of plant communities, and evaluate their relationships with environmental gradients. TWINSPAN classification of the vegetation plots and species suggests that the three main vegetation zones (mangroves, salt meadow/marsh, and freshwater swamp) can be divided into six broad vegetation communities named as follows: (A) Avicennia marina, (B) Juncus kraussii sea rush, (C) Leptocarpus similis salt meadow, (D) Baumea juncea sedges, (E) Leptospermum scoparium shrubland, (F) Typha orientalis/Cordyline australis swamp forest. DECORANA ordination reveals a gradient of communities from mangrove through salt meadow to shrubland then to swamp forest. The pattern of species distribution from salt to freshwater results from the interaction between species and the physical constraints of the salinity and freshwater inundation gradients. This pattern accounts for c. 77% of the current floristic variation in the modern vegetation, indicated by the different vegetation communities exhibiting similar distribution patterns along the estuarine to freshwater gradient.
An open access copy of this article is available from the publishers website. The productivity and decomposition of Typha orientalis at Kaitoke Swamp on Great Barrier Island, New Zealand, were measured to determine the annual dynamics of its biomass. These interactions, including peat accumulation under nutrient-rich conditions, are often poorly understood. Annual productivity and maximum "standing" above-surface and below-surface biomass were measured using sequential harvest plots. Decomposition was determined using recently dead T. orientalis leaves in mesh litter bags placed on, above, and below the swamp surface. The annual productivity of T. orientalis (c. 3 kg m-2) is within world-wide estimates for swamp wetland species. The order of decomposition of leaf litter at Kaitoke Swamp is: below surface > surface > above surface. Litter bag mesh size did not affect decomposition processes, indicating that larger decomposer animals probably do not have a significant influence on biomass loss in the site. Peat accumulation was estimated based on observations and measurements of the entrainment process. T. orientalis had low estimated peat accumulation, with 6.5% (0.19 kg m -2 yr-1) of the annual production remaining after all components had been underground for 5 years. Consequently a large amount of the annual production of biomass is lost from the site. The ratio of maximum biomass to annual productivity was 2.2, also indicating low biomass accumulation.
An open access copy of this article is available from the publishers website. Chromosome numbers of 2n = 50 have been determined from clones of the single wild plant of Pennantia baylisiana as well as of a seedling from this plant. In addition the same number was determined for P. corymbosa and the hybrids P. baylisiana x P. endlicheri and P. baylisiana x P. corymbosa.
An open access copy of this article is available from the publishers website. Achenes of Cirsium vulgare germinated at constant temperatures of 7-32�C. Fresh achenes had a higher optimum temperature of germination (23.5�C) than older achenes, and also germinated more slowly and had a lower maximum level of germination. At depths of 2 cm achenes either germinated or were destroyed. At greater depths the achenes showed an exponential decay rate in viability with time. Germination was synchronous with rainfall pattern over the summer, although subsequent germination may occur if achenes are brought to the surface. Young seedlings were not damaged by frosts of -2�C. After germination a major root system developed rapidly, whilst a rosette more slowly formed above ground. Rosettes increased in diameter until the winter when growth ceased, although horizontal growth was reinitiated if the rosette became damaged. In late winter or early spring vertical growth is initiated, leading to formation of a bushy plant with subsequent flowering and production of achenes. C. vulgare flowers throughout spring and summer with maximum number of plants flowering in late spring or early summer. Each capitulum holds c 200 achenes and a large plant may produce > 50 000 fertile achenes. Afte the capitulum has matured the achenes are wind dispersed. However, despite the presence of a pappus the majority of achenes fall within a circle of radius 1.5 times the height of the parent plant. In conjunction with the production of non-viable achenes through self-fertilisation, this is expected to result in marginal spread of this species from existing infestations.
An open access copy of this article is available from the publishers website. Phormium tenax, studied on Tiritiri Matangi Island and in Auckland, reproduces asexually by offsets and sexually by large inflorescences. Flowers are protandrous hermaphrodites that exhibit partial dichogamy and herkogamy. The pollen or the stigma are presented sequentially for initial contact with floral visitors. Nectar rewards are greatest during the male phase of flowering. Shape and configuration of flowers ensures that large birds are the most likely pollinators. Two honeyeaters (Meliphagidae), tui Prosthemadera novaeseelandiae and bellbird Anthornis melanura were the most frequent visitors and pollinators although some introduced bird species also commonly visited, especially in Auckland City. Many flowers appear to function solely as pollen donors.
An open access copy of this article is available from the publishers website. The floral biology and breeding system of pohutukawa (Metrosideros excelsa, Myrtaceae), a mass-flowering tree of northern New Zealand coastlines, were examined. Trees flower over a peak period of 2 weeks, and compound inflorescences contain an average of 14.3 showy, hermaphrodite, red brush flowers that remain open for 7 days. A brief female flower stage (mean duration 1.3 d) is followed by the main hermaphrodite phase that lasts for 4 days. Neither dichogamy nor herkogamy is important in preventing pollen and stigma interference. Pollen is highly viable (93.6%), and stigma receptivity extends for at least 9 days, as indicated by peroxidase activity, pollen germination, pollen tube length 24 h after pollination, and seed set. Stigmatic exudate production appears to increase up to 5 days post-anthesis. On average, flowers produce 46 ?l nectar per day, containing 18% (w/v) sucrose. Floral design and display of pohutukawa are consistent with high levels of autogamous and geitonogamous self-pollination. Controlled pollination experiments were used to assess the effect of self- and cross- pollen and a pollen mixture from five unrelated parents on capsule and seed production, and on pollen tube growth in seven trees. Three trees in the experiment were self-incompatible, as quantified by the index of self-incompatibility (ISI), indicating that natural populations may consist of a mosaic of self-compatible and incompatible individuals. Self-incompatibility is late-acting as pollen tubes from selfs and crosses reached the ovary simultaneously at 10-15 d after pollination. In common with other Myrtaceae, the seed/ovule ratio in pohutukawa is low and this is likely to be genetically determined rather than limited by stigmatic pollen load. Germination of fertile seeds from all pollination treatments was equally high (98.4%), indicating that no inbreeding depression is acting at this stage of the life cycle. The pollen/ovule ratio of 462.5 (s.e. �43.3) places the breeding system of pohutukawa between facultative selfing and facultative outcrossing.
Restiad bogs dominated by Sporadanthus traversii on Chatham Island, New Zealand, were sampled to correlate vegetation patterns and peat properties, and to compare with restiad systems dominated by Sporadanthus ferrugineus and Empodisma minus in the Waikato region, North Island, New Zealand. Classification and ordination resulted in five groups that reflected a disturbance gradient. The largest S. traversii group, which comprised plots from central, relatively intact bogs, had the lowest levels of total nitrogen (mean 1.20 mg cm-3), total phosphorus (mean 0.057 mg cm-3), total potassium (mean 0.083 mg cm-3), and available phosphorus (mean 18.6 μg cm-3). Modification by drainage, stock, and fires resulted in a decline of S. traversii and an increase of Gleichenia dicarpa fern cover, together with elevated peat nutrient levels and higher bulk density. Compared with peat dominated by Sporadanthus ferrugineus or Empodisma minus in relatively unmodified Waikato restiad bogs, Chatham Island peat under S. traversii has significantly higher total potassium, total nitrogen, available phosphorus, bulk density, and von Post decomposition indices, and significantly lower pH. Sporadanthus traversii and Empodisma minus have similar ecological roles in restiad bog development, occupying a relatively wide nutrient range, and regenerating readily from seed after fire. Despite differences in root morphology, S. traversii and E. minus are the major peat formers in raised restiad bogs on Chatham Island and in Waikato, respectively, and could be regarded as ecological equivalents. The final, definitive version of this article has been published in the Journal, New Zealand Journal of Botany, 42(2), (2004), (c) Royal Society of New Zealand at the Royal Society of New Zealand Journals Online webpages.
The agaric Crinipellis perniciosa (Tricholomataceae) is a hemibiotrophic pathogen which causes witches' broom disease of cacao and has recently decimated the Brazilian cacao industry. In addition to the pathogenic cacao (C-) biotype, other biotypes are found in association with unrelated plant taxa, notably bignoniaceous lianas (L-biotype), solanaceous hosts (S-biotype), and the shrub Heteropferys acutifolia (H-biotype). The C-and S-biotypes are non-outcrossing and form broom symptoms on hosts, whereas the L-biotype is outcrossing and asymptomatic. Phylogenetic analysis of several regions of the rRNA locus revealed near identity between C- and S-biotype isolates from diverse locations, with the L- and H-biotypes forming separate groupings. Preliminary analysis of sequence data from Moniliophthora roreri, causal agent of frosty pod disease, indicates that this morphologically distinct pathogen may be closely related to C. pernicinsa. Similarities in host infection between C. perniciosa and M. roreri have previously been noted but it is difficult to reconcile the gross morphological differences. Pairings between C. perniciosa and M. roreri gave rise to a clamped dikaryotic mycelium suggestive of a hybridisation event.
An open access copy of this article is available from the publishers website. Evolution in the genus Pratia (Campanulaceae) has been studied using a variety of techniques. The distribution of chromosome races in P. angulata has been plotted and results suggest that although they generally occupy different geographic areas there are large areas of overlap. No consistent morphological differences were found between these chromosome races. The existence of hybrids between P. angulata and P. perpusilla with 11x and 13x chromosome numbers has been established using genomic in situ hybridization (GISH), and random amplified polymorphic DNA (RAPD) analysis suggests several independent origins for these hybrids. Artificial hybridization studies showed a high degree of compatibility in almost all the combinations that were attempted. DNA sequences derived from both the nuclear genome (internal transcribed spacer of the rDNA locus, ITS) and chloroplast genomes (trnL intron and trnL-trnF spacer) were used to construct phylogenies. Colensoa physaloides has been shown to be distinct from the New Zealand species of Pratia and was used as an outgroup to root the phylogenetic trees. A significant finding is that P. macrodon is sister to the other New Zealand species. DNA sequence data also confirm the hybrid origin of the 11x and 13x plants and show that P. perpusilla is the maternal parent of the 11x plants and P. angulata is the maternal parent of the 13x ones. The origin of the putative hybrid plants with the 12x chromosome number remains to be elucidated.
An open access copy of this article is available from the publishers website. Growth and survival of kohekohe (Dysoxylum spectabile) seedlings planted in forest gaps and in non-gap micro-environments were monitored in Kauaeranga valley, near Thames, New Zealand. Seedlings in gaps and on gap edges grew faster than seedlings in darker forest environments. Seedlings protected from vertebrate browsing (mostly possum) grew faster and survived better than unprotected seedlings. Although browse appeared to be the primary cause of mortality, disease and damage from falling debris were also significant.
An open access copy of this article is available from the publishers website. A molecular phylogenetic analysis of New Zealand Coprosma using the internal transcribed spacer (ITS) and external transcribed spacer (ETS) regions of nrDNA discovered a consistent ITS sequence difference of eight base pairs between multiple samples of the widespread Coprosma obconica subsp. obconica and samples of the North Cape ultramafic endemic subsp. distantia. These DNA sequence results, coupled with those differences already described for both subspecies and the subsequent discovery of significant differences in the pyrene morphology of both subspecies, indicate that C. obconica subsp. distantia should be elevated to species rank. The necessary combination at the rank of species is made in this paper.
A new combination, Hebe paludosa, is made for plants first described as Veronica salicifolia var . paludosa and later treated as Hebe salicifolia var . paludosa. H. paludosa is typically a plant o f lowland mesotrophic wetlands and is most abundant in south Westland around and immediately north o f the glaciers district . H. paludosa is readily distinguished from H. salicifolia through its cytology , distinctive diffusely branching habit, brittl e branchlets, yellow-green faintly glaucous-tinge d leaves, conspicuous decurved and twisted acumen, flowers which have a longer corolla tube, acute corolla lobes which usually project forward, and preference for mesotrophic wetland habitats.
Species composition and life history traits of trees in native forests in the dry zone of Fiji were investigated. Areas receiving less than 2500 mm yr-1 of rain and covered with native forest were identified using maps, aerial photographs, estimated climate (WorldClim), and field reconaissance. Ten forest remnants were identified and species lists and data on natural history and disturbance were compiled. Cluster analysis and DECORANA identified two principal forest types, moist forest (MF) and tropical dry forest (TDF), each defined by unique climate, species composition, and tree life history characteristics. TDF (reported for the first time from Fiji) has a pronounced dry season (5 consecutive months with <100 mm rainfall each) and several deciduous canopy species. MF lacks a pronounced dry season and has few deciduous species. The amount and variability of rainfall seem to influence the type of forest in a particular location and disturbance is negatively correlated with precipitation. TDF are probably Fiji’s most endangered ecosystems.
The flora and vegetation of an area in north-eastern Vanua Levu that is part of Fiji's last major system of mesic forest were studied and revealed a mosaic of vegetation types, including mesic sclerophyll forest, transition forest, stunted Dacrydium nidulum forest, mangrove forest, montane forest, brackish and freshwater wetlands, and disturbed landscapes. This is much more diverse than indicated by the previous "dry forest" label. The flora comprises more than 268 native species, several of which are rare or narrowly distributed. Relatively large and undisturbed stretches of vegetation and the presence of rare and novel species and vegetation types suggest that the landowners should be given every possible assistance in protecting this unique landscape.