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Studies on Pleonosporium and Mesothamnion (Ceramiaceae, Rhodophyta) with a description of a new species from Natal
Abstract
Ontogenetic studies of procarps of Mesothamnion caribaeum Boergesen, the type species of the genus, show that it does not differ in procarp structure from Pleonosporium. It is concluded that Pleonosporium cannot stand as a genus on its polysporangiate character alone, so the tetrasporangia- and polysporangia-bearing genus Mesothamnion Boergesen as well as the tetrasporangia-bearing genus Compsothamnionella Itono are combined with Pleonosporium Naegeli. A new species of Pleonosporium, P. callicladum, is described from Natal.
... The genus Pleonosporium Nägeli (1862) described based on Conferva borreri Smith (1807; = Callithamnion borreri (Smith) C. Agardh, 1828) is characterized by a filamentous thallus, distichous alternate branching, polysporous meiosporangia, and terminally borne cystocarps. The generic concept of Pleonosporium was redefined by Norris (1985) who considered Mesothamnion Børgesen (1917) and Compsothamnionella Itono (1977) to be congeneric with Pleonosporium on the basis of their similar female reproductive structures. Previously used features of branching mode and polysporangia are no longer useful as generic characters (Norris, 1985;Kim and Lee, 1988). ...
... The generic concept of Pleonosporium was redefined by Norris (1985) who considered Mesothamnion Børgesen (1917) and Compsothamnionella Itono (1977) to be congeneric with Pleonosporium on the basis of their similar female reproductive structures. Previously used features of branching mode and polysporangia are no longer useful as generic characters (Norris, 1985;Kim and Lee, 1988). ...
... The genus is distinguished by its subapical procarps on short determinate branches; carpogonial branches 4-celled, borne on the subterminal cell of short, lateral, 3 (-5)-celled branches, with 2 periaxial cells on the third cell; the 3 sterile cells (terminal cell and 2 periaxial cells) enlarge and become rounded. Post-fertilization the auxiliary cell, cut off from supporting cell, leading to carposporophyte with produces successive rounded groups of carposporangia surrounded by involucral filaments and spermatangial clusters pedicellate on filamentous branches (Norris, 1985;Womersley and Wollaston, 1998;Guiry and Guiry 2017). ...
The tribe Spongoclonieae (Ceramiaceae subfam. Spongoclonioideae) is represented on the Atlantic and Pacific coasts of Mexico by two genera: Pleonosporium with eight species and Spongoclonium with a single species. Pleonosporium boergesenii and P. borreri are both new records for Atlantic Mexico. Known in Pacific and Atlantic Mexico, P. rhizoideum has the widest distribution, while P. pygmaeum and P. vancouverianum have only a few records in the study area. Pleonosporium mexicanum is found mainly in tropical Pacific Mexico, and P. globuliferum has a discontinuous distribution in the Gulf of California and then in Salina Cruz, Oaxaca. In the case of P. squarrulosum morphological and genetic comparisons are needed to verify its presence in Mexico. The report of Spongoclonium caribaeum from intertidal Veracruz (Gulf of Mexico) represents the second record of this species for the Atlantic coast of Mexico. Detailed descriptions, information on nomenclature, collections studied, distribution and habitat are provided for each of the species. Measurements of vegetative characters and reproductive structures provide a consistent basis for identifying Atlantic and Pacific Mexican species of Pleonosporium and Spongoclonium.
... Ardré et al. (1982) após examinarem o sintipo de Mesothamnion boergesenii A.B. Joly verificaram que estruturas masculinas sésseis e pedunculadas estavam presentes. Norris (1985) após estudar as estruturas reprodutivas femininas de ambos os gêneros, concluiu que estas não eram suficientemente distintas para manter Mesothamnion e Pleonosporium como gêneros separados. Norris (1985) reduziu os gêneros Mesothamnion e Compsothamniella Itono à sinonímia de Pleonosporium. ...
... Norris (1985) após estudar as estruturas reprodutivas femininas de ambos os gêneros, concluiu que estas não eram suficientemente distintas para manter Mesothamnion e Pleonosporium como gêneros separados. Norris (1985) reduziu os gêneros Mesothamnion e Compsothamniella Itono à sinonímia de Pleonosporium. Este autor propôs as seguintes combinações novas: Pleonosporium caribaeum (Børgesen) R.E. ...
... Espécimes de Pleonosporium caribaeum do Japão (Itono, 1971(Itono, , 1977, África do Sul (Norris, 1985) e Porto Rico são conhecidas por formar tetrasporângios e polisporângios, contudo, as espécies da Coréia formam somente polisporângios. P. boergesenii e P. yagii também podem apresentar tetrasporângios e polisporângios (Norris, 1985). ...
75 Introdução A família Ceramiaceae pertence a ordem Ceramiales e foi estabelecida por Du-mortier (1822), sendo tipificada por Ceramium Roth, possuindo mais de 100 de 2-3 es-permatângios, ramo carpogonial com 4 células, gonimoblastos nus ou envoltos por fila-mentos frouxamente dispostos, tetrasporângios tetraédricos ou cruciados, presença de polisporângios em algumas espécies (Itono 1977, Maggs & Hommersand 1993, Womers-ley 1998). No Brasil, devido a suas dimens›es continentais, ainda se fazem necessârios estudos de inventârios florísticos em vârias regi›es, pois os dados s‹o incompletos e fragmentados, existindo ainda, vários grupos taxonômicos a serem estudados, so-bretudo na região Nordeste, a exemplo das Ceramiaceae. Situa-se na região nordeste do Brasil a qual se caracteriza pela presença de uma flora tropical rica, águas oligotróficas e abundância de substratos duros, propí-cios ao crescimento de macroalgas marinhas (Horta et al. 2001. O litoral da Bahia é o mais extenso do Brasil com 1.103 km, tendo, como limite norte, a barra do Rio Real, no município de Jandaíra, e, como limite sul, a barra do Riacho Doce, município de Mucuri. O litoral abriga a flora ficológica mais diversificada do nordeste e apresenta grande diversidade de ambientes: praias arenosas, recifes de corais, formações de arenito, costões rochosos e manguezais. Esse litoral faz parte da Região Tropical que se caracteriza pela presença de flora relativamente rica, estabelecida predominantemente sobre recifes de arenito,
... Note: Due to the presence of tetrasporangia, rather than polysporangia (although octosporangia are occasionally observed), and the fact that female gametophytes are only rarely collected, the species can be misinterpreted as one of many small Callithamnion or Aglaothamnion species present along the South African coastline. Contrary to the ideas of Norris (1985), the difference between tetrasporangia and polysporangia is considered an adequate generic character by Womersley & Wollaston (1998). Hence the latter authors keep Pleonosporium, characterized by polysporangia, separate from the genera characterized by tetrasporangia. ...
... Pleonosporium (Ceramiales) is characterized by having polysporangia (Abbott & Hollenberg 1976); some species may have both tetrasporangia and polysporangia on the same plant (e.g. Norris 1985). The present study was undertaken to examine the ultrastructure of polysporangial development in Pleonosporium vancouverianum (1. ...
Ultrastructural features of red algal polysporogenesis are reported for the first time. Polysporangia of Pieonosporium vancouverianum (Ceramiales) are initiated near the apex of multinucleate vegetative cells by lateral protrusions which are separated by basally directed wall invaginations. Young sporocytes contain two, four, or five nuclei, each of which undergoes meiosis; 8, 16 or 20 uninucleate spores are ultimately formed within the mature polysporangia. In addition to the large axial nuclei, the cytoplasm of meiotic polysporangia also contains mitochondria, small vacuoles and several chloroplasts arranged in a peripheral layer. Tripartite synaptonemal complexes occur within the nucleoplasm during prophase I. A polar ring was observed adjacent to the nuclear envelope of a nucleus in interkinesis. At metaphase II the nuclear envelope forms polar pockets with nuclear pores, and each nucleus contains a chromosomal plate with associated electron dense amorphous kinetochores. Perinuclear endoplasmic reticulum is evident during metaphase II. Prior to cytokinesis, polysporangia contain localized regions consisting of one irregularly shaped nucleus surrounded by several chloroplasts, starch granules and mitochondria. Each of these areas is separated by enlarged granular vesicles which are associated with Golgi activity, accumulation of endoplasmic reticulum and increase in the number of chloroplasts. The uninucleate regions are then divided by several simultaneous, centripetal invaginations of the plasmalemma which form cleavage furrows. Only the early stages of lateral polysporangial initials and production of multiple nuclei during this process are significantly different from the homologous process of tetrasporogenesis.
... The structure of the young female axis, in which the apical cell remains terminal and three pericentral cells are formed, aligns Callithamnion decompositum with Compsothamnion (cf. Gordon-Mills & Wollaston, 1990) and distances it from Mesothamnion and Pleonosporium, in which the apical cell is displaced laterally and only two pericentral cells develop (Norris, 1985;Ardre & al., 1982). Compsothamnion presently consists of only two species, C. thuyoides and C. gracillimum, which are restricted to the N. E. Atlantic and the Mediterranean (Dixon, 1960). ...
... Mesothamnion (Børgesen 1917), a genus that was recognized by Taylor (1960), was initialy merged within Pleonosporium by Norris (1985) but was later merged within Spongoclonium (Sonder 1855) from the evidence presented by Womersley and Wollaston (1998). Searlesia was established by Schneider and Eiseman (1979) Figs 27 & 28. ...
Taylor's (1960) floristic treatment of the benthic marine algae of the tropical and subtropical western Atlantic and Wynne's (2011) "checklist: third revision" serve as benchmarks in a review of changes made in the past half-century period. There has been a great increase in the number of recognized taxa of red, brown and green algae at all taxonomic ranks: from 758 to 1,393 species, an increase of 84%; from 231 to 406 genera, an increase of 75%; and from 63 to 106 families, an increase of 68%. In regard to recognized infraspecific taxa, the increase was less dramatic, from 140 to 185, thus a 32% change in the 50-year period. This review addresses the question: What factors were responsible for this proliferation of taxa that are now recognized in this domain of the tropical and subtropical western Atlantic? The answer is that many reasons contributed to these changes. Foremost among these causes have been the advances in gene-sequencing technologies. Revised phylogenetic relationships have led to many genera being divided into more than one genus, as well as new families and orders being delineated. Numerous examples of cryptic species have been discovered by gene-sequence and DNA-bar coding studies. This trend is depicted by case studies. Examples of genera being divided are Galaxaura, Liagora and Laurencia. Tricleocarpa and Dichotomaria have been segregated from Galaxaura. Trichogloeopsis, Ganonema, Izziella, Yamadaella, and Titanophycus have been segregated from Liagora. Chondrophycus, Osmundea, Palisada, and Yuzurura have been segregated from Laurencia. Examples are given of other genera present in this region of the western Atlantic that have been split up. Many genera have increased in terms of the number of species now assigned to them. Taylor's (1960) treatment recognized only two species in Hypoglossum, whereas Wynne's (2011) checklist contained a total of 9 species of Hypoglossum. Taylor's account included only two species of Botryocladia, but this number had grown to 15 in Wynne's checklist. Examples of new genera and species occurring in the region of the western Atlantic are given, and examples of taxa being newly reported for this domain are provided. An increase in the number of phycologists in Latin and South America, exploration of previously unexplored regions, and the increasing use of SCUBA for collecting and at greater depths have all contributed to the increase in the number of algal taxa that are now recognized as occurring in the tropical and subtropical western Atlantic.
... Una de sus especies, Pleonosporium caribaeum (Børgesen) R.E. Norris fue originalmente descrita como una especie del género Mesothamnion Børgesen (Børgesen 1917), más tarde otros estudios mencionaron descripciones de nuevas especies con características intermedias, poniendo en duda la distinción de estos dos taxones, posteriormente Norris (1985) realizó una reevaluación de las estructuras reproductivas de ambos géneros y encontró que los caracteres del procarpo de Mesothamnion eran idénticos a los de Pleonosporium, concluyendo que los caracteres diagnósticos que diferenciaban estos taxones no eran lo suficientemente sólidos y establece al género Mesothamnion como un sinónimo de Pleonosporium. ...
Pleonosporium caribaeum (Børgesen) R.E. Norris, a red alga belonging to the family Ceramiaceae, is presented as a new report of genus and species for the Venezuelan coast, characterized by producing tetrasporangia as well as polysporangia, polystichous branching (alternate radial), incurvate branchelets and spermatangial heads, cylindrical and pedicellate. It was collected in meadows of Thalassia testudinum Banks ex König, near the town of Varadero, Morrocoy National Park, Falcon State, Venezuela. Its specimens are described and pictured.
... Patterns of division of the apical cell are correlated with the primary growth patterns that tend to be diagnostic of tribes (Moe and Silva 1979). A 1/4 spiral branching pattern in species that form only one or two periaxial cells per indeterminate-axial cell seems to be encountered only in some genera of the Callithamnieae and Spongoclonieae (Itono 1977, Norris 1985, Wollaston 1990), a 1/2 spiral being the norm in many Callithamnieae, most Spongoclonieae, and all Compsothamnieae and Ptiloteae. Although several unrelated groups exhibit a decussate branching pattern when bearing opposite determinate laterals, the combination in Sciurothamnion of 1/4 spiral first-lateral phyllotaxy followed by the development of a second periaxial cell directly opposite the first is unique among the Ceramiaceae. ...
A new ceramiaceous alga, Sciurothamnion stegengae De Clerck et Kraft, gen. et sp. nov., is described from the western Indian Ocean and the Philippines. Sciurothamnion appears related to the tribe Callithamnieae on the basis of the position and composition of its procarps and by the majority of post-fertilization events. It differs, however, from all current members of the tribe by the presence of two periaxial cells bearing determinate laterals per axial cell. Additionally, unlike any present representative of the subfamily Callithamnioideae, no intercalary foot cell is formed after diploidization of the paired auxiliary cells. The genus is characterized by a terminal foot cell (“disposal cell”), which segregates the haploid nuclei of the diploidized auxiliary cell from the diploid zygote nucleus. The nature of three types of foot cells reported in the Ceramiaceae (intercalary foot cells containing only haploid nuclei, intercalary foot cells containing haploid nuclei and a diploid nucleus, and terminal foot cells containing only haploid nuclei) is discussed.
Zonariophila semiendophytica is described as a new genus and species from the coast of the East Cape, South Africa. It is characterized by a single large elongate basal cell immersed in the thallus of Zonaria subarticulata (lamour.) Papenf.; this laterally compressed cell gives rise, on both edges, to several short (up to 2.5 mm), uncorticated, erect, sparingly branched filaments. The position and structure of the procarp (the subapical cell in a determinate female fertile filament bears two sterile pericentral cells and one fertile pericentral cell, the latter with one sterile cell and a four-celled carpogonial filament), and the development of a single involucral filament from the hypogenous cell, put this genus in the immediate vicinity of Pleonosporium, and placement in the tribe Compsothamnieae is proposed.
Evidence is presented for the occurrence of one species of Compsothamnionella on the coast of the eastern Cape Province, South Africa. Compsothamnionella is once more separated from Pleonosporium, the chief differences being: (i) a more complex cortication in Compsothamnionella, involving filaments that connect laterals of alternate segments, in contrast to absent cortication or of loose rhizoidal filaments not connecting laterals in Pleonosporium; (ii) development of the procarp on the second to fifth cell below the apex of the female fertile filament in Compsothamnionella, in contrast to Pleonosporium where the procarp develops on the subapical cell only. It is concluded that the tribal position of Compsothamnionella is intermediate between the Ptiloteae and the Compsothamnieae. The South African species is new to science, and the name C. sciadophila is proposed.
Maggs, C. A. & L'Hardy‐Halos, M.‐T.: Nuclear staining in algal herbarium material: a reappraisal of the holotype of Callithamnion decompositum J. Agardh (Rhodophyta). – Taxon 42: 521–530. 1993. – ISSN 0040‐0262.
The taxonomic importance of uninucleate vs. multinucleate vegetative cells in the Ceramiaceae is emphasized. It has been possible to make visible nuclei in old material, including type specimens, using aceto‐carmine and aceto‐iron‐haematoxylin stains. The holotypes of Ceramium roseum and Callithamnion fasciculatum (currently known as Callithamnion roseum and Pleonosporium borreri var. fasciculatum ) have uninucleate cells and belong to Aglaothamnion. In contrast, the holotype of Callithamnion decompositum , a name that has been applied to collections of at least two uninucleate taxa, has multinucleate cells; its morphological and cytological details agree with those of specimens collected in France and Ireland that were previously thought to represent an undescribed species. Female reproductive morphology (described from a thallus with gametangia in addition to tetrasporangia), in conjunction with habit and vegetative features, indicates that this species belongs to Compsothamnion (Compsothamnieae) , as a third species, being distinguished from C. thuyoides and C. gracillimum by its sessile, lateral tetrasporangia. The required new combinations under Aglaothamnion and Compsothamnion are made.
The implementation of the REVIZEE Program significantly allowed advancing in the knowledge of the seaweeds from the Continental Shelf of Brazil. For the present study, samples collected by a rectangular dredge in five stations of Espírito Santo and Rio de Janeiro States, at depths of 36 to 124m (20,352ºS-22,883ºS; 037,620ºW-041,154ºW) were analyzed. In the laboratory, the epiphytes Ceramiaceae were observed in the following host species: Dictyopteris jamaicensis W. R. Taylor, Zonaria tournefortii (J.V.
Lamour.) Mont., Pterocladiella capillacea (S. G. Gmel.) Santel. & Hommers., Cryptonemia seminervis (C. Agardh) J. Agardh and Plocamium brasiliense (Grev. in J. St.-Hil.) M. Howe & W. R. Taylor. Eleven Ceramiaceae species were recorded: Aglaothamnion cf. priceanum Maggs, Guiry & Rueness, Antithamnionella atlantica (E. C. Oliveira) C. W. Schneid., A. bermudica C. W. Schneid. in Schneider & Searles, A. breviramosa (Dawson)
Wollaston in Womersley & Bailey, Callithamniella tingitana (Schousb. ex Bornet) Feldm.-Maz., Compsothamnion thuyoides (Sm.) F. Schmitz, Diplothamnion tetrastichum A. B.Joly & Yamaguishi in Joly et al., Pleonosporium boergesenii (A. B. Joly) R. E. Norris, Pterothamnion heteromorphum (J. Agardh) Athanas. & Kraft, Spermothamnion repens (Dillwyn) Rosenv. and Tiffaniella snyderiae? (Farl.) I. A. Abbott. Seven of these species were found in Espírito Santo State (Aglaothamnion cf. priceanum, Antithamnionella atlantica, A. bermudica, A. breviramosa, Pleonosporium boergesenii, Spermothamnion repens and Tiffaniella snyderiae?) and four in the Rio de Janeiro State (Callithamniella tingitana, Compsothamnion thuyoides, Diplothamnion tetrastichum and Pterothamnion heteromorphum). Some of these 11species are usually found in the North Hemisphere seas and represent new records for the Southern Atlantic waters (Aglaothamnion cf. priceanum, A. bermudica, Pterothamnion heteromorphum and Tiffaniella snyderiae?).
Floristic studies in the Cape Province, South Africa have recorded 87 taxa (including 2 varieties) of the family Ceramiaceae. The distribution of these taxa is discussed in relation to existing concepts of marine floristic provinces in this region. In the approximately 2000 km of coastline between the Orange River in the west and the Kei River in the east, the most dramatic change in floristic composition occurs between the Cape Peninsula and Cape Agulhas. This confirms the position of the `western overlap' described by previous marine biogeographers, separating the temperate west and south coast marine provinces. Further east, a less dramatic but still considerable change from Plettenberg Bay and Port Elizabeth eastward, representing the `eastern overlap', can be distinguished. The latter floristic boundary is much longer than the western transition zone. and it remains uncertain if and where further north, along the sub-tropical Natal coast, there is another relatively homogeneous flora.
A new species of Ceramiaceae, Compsothamnionella huismanii sp. nov. is described from southern Australia. It differs from the two other known species of Compsothamnionella (both from Japan) by its much larger cell and overall frond size. Complete post-fertilization details and male structures are described for the first time in the genus. The auxiliary cell is produced from one of the two pericentral cells on the fertile central cell of the female axis. The fertile central cell is the third to fifth cell below the apical cell. Up to five gonimolobe initials are produced from the auxiliary cell, each dividing to produce successively maturing gonimolobes composed of carposporangia of equal size. The apical cell of the fertile, axis, the sterile pericentral cell, and the lateral cell on the hypogenous cell divide to produce involucral branchlets which curve over the developing gonimoblast. The genus Compsothamnionella Itono appears to be closely related to Compsothamnion Naegeli and Antarcticothamnion Moe et Silva. These three genera should be grouped together in the Compsothamnieae, whereas Pleonosporium, Mesothamnion and Spongoclonium, which were included in Compsothamnieae by Kylin (1956), should probably be placed in the tribe Spongoclonieae. However further investigation on relationships of these and other genera are necessary before tribal features can be more surely defined.
The floristic relationships of the South African red algae have been evaluated by analyzing the distribution of more than 300 species found in Namibia, the West Cape, the East Cape and Natal in comparison with the species of other climatically determined biogeographic regions. Determinations of species’ affinities are based primarily on an assessment of shared advanced morphological traits. Over 60% of the red algal species of Namibia and the West Cape have their closest relationships with species occurring in the temperate floras of southern Australia, Tasmania and New Zealand or South America. The primary affinity of the East Cape and Natal floras is with the tropical flora of the Indian Ocean, but this region also includes major components related to species occurring in west and south Australia or Japan. It is concluded that the Rhodophytan flora of South Africa was assembled in response to paleoceanographic events and associated climatic changes that took place in the latter half of the Cenozoic and that the flora reached its present structure and species composition in late Oligocene and Miocene.
A checklist of 1058 species of benthic marine algae has been compiled for the tropical and subtropical W Atlantic, covering the region from North Carolina through S Brazil. This list comprises 655 species of Rhodophyceae, 150 of Phaeophyceae, and 253 of Chlorophyceae. -from Author
A total of 124 species of benthic marine algae is reported from the Palolo Deep National Marine Reserve on the island of Upolu (Western) Samoa (13°49′S, 171°45′W). Included in the catalogue are 88 Rhodophyceae, 12 Phaeophyceae and 24 Chlorophyceae. This represents the first survey of benthic marine algae for any site in the Samoan Archipelago in the last 76 years. A total of 90 species newly recorded for the region brings the total reported species to 288 (includes Cyanophyceae not reported here). This is about 68% of the current flora from, for example, nearby Fiji. Of the 11 sites investigated, the eastern algal rim of the main Deep (0–10-m depth) is the most diverse, with 68 species. The subtidal (up to 25 m deep) is also diverse with 57 species recorded. The least diverse of all the sites is the Borrow Pit with only six species.
Two hundred and ten species of marine algae, seagrasses and cyanobacteria are reported from the Dampier Archipelago, northwestern Western Australia. Included are 114 species of Rhodophyta, 50 species of Chlorophyta, 32 species of Phaeophyceae, 5 species of Cyanophyta and 9 species of seagrasses. This report presents the first detailed account of marine benthic algae from tropical Western Australia. Fifty-seven species are newly recorded for Western Australia, with five species (Codium dwarkense, Dictyota friabilis, Balliella subcorticata, Cottoniella amamiensis, Polysiphonia pentamera) also newly recorded for Australia. The algal flora of the region includes many elements common to tropical areas worldwide.
Classification of the red algae (Rhodoplantae) has under-gone significant change since the seminal work of Harald Kylin, ''Die Gattungen der Rhodophyceen,'' a half century ago. The number of genera has nearly doubled over this time period, at least in part due to recent molecular com-parative work. Information gleaned from gene-sequenc-ing analyses has resulted in a red algal classification that reflects a more accurate phylogenetic framework than that based solely on morphological data. This paper tab-ulates the known 834 genera of red algae today with tax-onomic synonyms and literature references reflecting the great change over fifty years.
The intertidal seaweed flora of Isipingo Beach, Natal, is described. Isipingo Beach lies on the sub-tropical east coast of
southern Africa and is the only east coast locality studied in detail by pioneering biogeographers. A total of 172 species
(37 chlorophytes, 26 phaeophytes and 109 rhodophytes) are recorded. A phycogeographical analysis of 124 species with sufficiently
documented distributions, shows that 69% are warm water species also known from the tropical coasts of Mozambique, Tanzania
and Kenya. The phycogeographical affinity of the Isipingo flora is certainly with sub-tropical and tropical floras.
The marine flora of the transition region between the warm temperate south coast and sub-tropical east coast of southern Africa
is very poorly documented. The seaweeds of Hluleka Nature Reserve, centrally placed along this transition, are described.
178 species (120 rhodophytes, 33 chlorophytes and 25 phaeophytes) are recorded, including 28 new records for the region, and
a new combination,Tiffaniella schmitziana (Barton) nov. comb. A biogeographical analysis of those species whose distribution is sufficiently known reveals that 65%
are warm water species, also occurring in tropical seas. Hluleka is thus towards the warmer end of the transition, and the
major discontinuity is sharply defined, occurring in the ca 130 km of coastline between Hluleka and the mouth of the Kei River.
It is probable that a rapid temperature gradient along this stretch of coast (change of 2°C in annual mean) is responsible
for the discontinuity.
Gymnophycus gen. nov. (Ceramiaceae, Rhodophyta) is a genus of two species of minute algae from eastern Australia. Plants consist of erect, alternate-distichously branched uncorticated axes. Procarps are formed on the subterminal cells of major axes, the carpogonial branch arising on the first of three pericentral cells, which also bears a sterile lateral cell. In G. hypsispermis sp. nov., from southern Queensland, axial growth ceases with initiation of procarps and carposporophytes are terminal. In G. hapsiphorus sp. nov., from Lord Howe Island, N.S.W., and One Tree Island, Queensland, growth of the lateral axis on the sub-hypogenous cell continues after procarp formation, displacing the carposporophytes laterally. Fertilization in both species appears to result in transfer of the zygote nucleus to either the third pericentral cell or the supporting cell, followed by fusion of the supporting cell with the third pericentral cell via a small connecting cell. These cells form a distinctive perforate arch at the distal end of the fertile axial cell and give rise to two gonimoblast initials which together produce up to seven gonimolobes of carposporangia. The hypogenous cell is also incorporated into the fusion product. Neither involucral nor any type of adventitious filaments are associated with the mature carposporophyte. Sessile tetrahedral tetrasporangia are produced in adaxial rows on lateral branches, and male gametophytes bear dense spermatangial heads in a similar position. Because of fusion cell and carposporophyte anomalies, Gymnophycus is only provisionally placed in the tribe Compsothamnieae, with which it shares vegetative and procarp features.
Gymnophycus gen. nov. (Ceramiaceae, Rhodophyta) is a genus of two species of minute algae from eastern Australia. Plants consist of erect, alternate-distichously branched uncorticated axes. Procarps are formed on the subterminal cells of major axes, the carpogonial branch arising on the first of three pericentral cells, which also bears a sterile lateral cell. In G. hypsispermis sp. nov., from southern Queensland, axial growth ceases with initiation of procarps and carposporophytes are terminal. In G. hapsiphorus sp. nov., from Lord Howe Island, N.S.W., and One Tree Island, Queensland, growth of the lateral axis on the sub-hypogenous cell continues after procarp formation, displacing the carposporophytes laterally. Fertilization in both species appears to result in transfer of the zygote nucleus to either the third pericentral cell or the supporting cell, followed by fusion of the supporting cell with the third pericentral cell via a small connecting cell. These cells form a distinctive perforate arch at the distal end of the fertile axial cell and give rise to two gonimoblast initials which together produce up to seven gonimolobes of carposporangia. The hypogenous cell is also incorporated into the fusion product. Neither involucral nor any type of adventitious filaments are associated with the mature carposporophyte. Sessile tetrahedral tetrasporangia are produced in adaxial rows on lateral branches, and male gametophytes bear dense spermatangial heads in a similar position. Because of fusion cell and carposporophyte anomalies, Gymnophycus is only provisionally placed in the tribe Compsothamnieae, with which it shares vegetative and procarp features.
Two new propagule-farming red algae from southern Australia, Deucalion levringii (Lindauer) gen. et comb. nov. and Anisoschizus propaguli gen. et sp. nov., are described and defined largely on their development in laboratory culture. Deucalion is included in the tribe Compsothamnieae on the basis of its subapical procarp and alternate distichous branching. It differs from the other genera included in that tribe in that it produces 3-celled propagules, polysporangia, a subapical cell of the fertile axis which bears 3 pericentral cells, and an apparently post-fertilization involucre which develops from the hypogenous and sub-hypogenous cells of the fertile axis. Its gametophyte morphology has been elucidated in culture, as only sporophytes are known from the field. Gametophytes do not appear to produce propagules. Anisoschizus is provisionally included in the tribe Spermothamnieae on the basis of its subdichotomous branching, possession of a prostrate system and the production of polysporangia. It differs from the other genera of the tribe in the production of 2-celled propagules. Observations on the germination of the “monosporangia” of Mazoyerella arachnoidea and Monosporus spp. indicate that they are analagous to the propagules of Deucalion and Anisoschizus. The nature of these propagules and their role in recycling the parent plant are discussed and contrasted with true monosporangia. It is recommended that Monosporus be maintained as a form genus containing representatives from more than one tribe, as exemplified by plants from Lord Howe I. provisionally identified as M. indicus Boergesen which have both prostrate and erect, as opposed to only erect, axes.
Die Gattungen der Rhodophyceen Die Meeresalgen der Juan Fernandez lnseln
- H C W K Kylin
- Frrlag
- Lund
- T Levring
KYLIN, H. (1956). Die Gattungen der Rhodophyceen. C. W. K. Gleerups Frrlag, Lund. xvi + 669 pp. LEVRING, T. (1941). Die Meeresalgen der Juan Fernandez lnseln. In The Natural History of Juan Fernandez and Easter Island (Skottsberg, C., editor), 2(22): 610-670.
Contribuigao ao conhecimento da flora ficolrgica marinha da Baia de Santos e Arredores. Univ. S&o Paulo, Fac. FiL, Ci~nc. e Let The marine red algae in the vicinity of the biological station at Friday Harbor
- A B Joly
- Pp
- H Kylin
JOLY, A. B. (1957). Contribuigao ao conhecimento da flora ficolrgica marinha da Baia de Santos e Arredores. Univ. S&o Paulo, Fac. FiL, Ci~nc. e Let., BoL 217, Bot. 14, 199 pp. KYLIN, H. (1925). The marine red algae in the vicinity of the biological station at Friday Harbor, Washington. Acta Univ. Lund., 21(9): 1-87.
The genera Callithamnion, Aglaothamnion, Seirospora, Pleonosporium and Mesothamnion (Ceramiaceae, Rhodophyta) in southern
- H Itono
ITONO, H. (1971). The genera Callithamnion,
Aglaothamnion, Seirospora, Pleonosporium and
Mesothamnion (Ceramiaceae, Rhodophyta) in
southern Japan. Mere. Fac. Fish. Kagoshima
Univ., 20: 217-237.
Recherches sur les C~ramiacbes de la Mbditerranbe occidentale Die Algenvegetation des Golfes yon Neapel Deucalion gen. nov. and Anisoschizus gen. nov. (Ceramiaceae, Ceramilaes), two new propagule-forming red algae from southern Australia
- R E Norris Feldmann-Mazoyer
- G Minerva
- Alger
- G Funk
- Pp
- J M Huisman
- G Z Kraft
R.E. Norris FELDMANN-MAzOYER, G. (1940). Recherches sur les C~ramiacbes de la Mbditerranbe occidentale. 510 pp. Minerva, Alger. FUNK, G. (1927). Die Algenvegetation des Golfes yon Neapel. Pubbl. Staz. zool. Napoli, 7, 507 pp. HUISMAN, J. M. & KRAFT, G. Z. (1982). Deucalion gen. nov. and Anisoschizus gen. nov. (Ceramiaceae, Ceramilaes), two new propagule-forming red algae from southern Australia. J. Phycol., 18: 177-192.
Two new marine algae from Japan
- Y Yamada
YAMADA, Y. 0968). Two new marine algae from Japan.
J. Jap. Bot., 43: 372-377.
(Accepted 20 October 1984)
The marine red algae in the vicinity of the biological station at Friday Harbor
KYLIN, H. (1925). The marine red algae in the vicinity
of the biological station at Friday Harbor,
Washington. Acta Univ. Lund., 21(9): 1-87.
The marine algae of the Danish West Indies. III. Rhodophyceae. Dansk bot
BOERGESEN, F. (1916). The marine algae of the Danish
West Indies. III. Rhodophyceae. Dansk bot.
Ark., 3: 145-240.
Die Algenvegetation des Golfes yon Neapel
FUNK, G. (1927). Die Algenvegetation des Golfes yon
Neapel. Pubbl. Staz. zool. Napoli, 7, 507 pp.
Recherches sur les Céramiacées de la Méditerranée occidentale
- G Feldmann-Mazoyer
Recherches sur les C~ramiacbes de la Mbditerranbe occidentale
- G Feldmann-Mazoyer
FELDMANN-MAzOYER, G. (1940). Recherches sur les
C~ramiacbes de la Mbditerranbe occidentale.
510 pp. Minerva, Alger.
The marine red algae in the vicinity of the biological station at Friday Harbor, Washington
- H Kylin
KYLIN, H. (1925). The marine red algae in the vicinity
of the biological station at Friday Harbor,
Washington. Acta Univ. Lund., 21(9): 1-87.
Die Gattungen der Rhodophyceen. C. W. K. Gleerups Frrlag, Lund. xvi + 669 pp
- H Kylin
KYLIN, H. (1956). Die Gattungen der Rhodophyceen. C.
W. K. Gleerups Frrlag, Lund. xvi + 669 pp.