Spermatangial Conceptacles Research Articles

Gracilaria khanjanapajiae sp. nov. (Gracilariales, Rhodophyta) from the Andaman coast of Thailand

ABSTRACT Taxonomy and diversity of the Gracilariaceae has been increasingly investigated by using integrated morphological and genetic approaches. The Indo-Pacific is likely a hotspot for diversity of these macroalgae. Collections of flattened Gracilaria samples from Natai beach, Andaman coast of Thailand, were morphologically and genetically analysed. Our results clearly indicated the presence of a new species, G. khanjanapajiae sp. nov., in Thailand. In comparison to other known Indo-Pacific flattened species, G. khanjanapajiae can be distinguished by its dentate blade margin, deep spermatangial conceptacles (verrucosa-type) and numerous lateral and basal nutritive filaments within mature cystocarps. This new species resembles G. srilankia in having similar branching pattern and male reproductive structures, but differs in blade margin features. Phylogenetically, G. khanjanapajiae was more closely related to G. spinulosa from Taiwan than other Thai and Indian Ocean species. This present study highlights the continuing discovery of Gracilaria diversity and distribution in the tropical Indo-Pacific.

Detail description of Lithophyllum okamurae (Lithophylloideae, Corallinales), a widely distributed crustose coralline alga in marine ecosystems

Lithophyllum okamurae is one of the important encrusting coralline algae, which plays important roles as primary producer, carbonate sediment builder, and habitat provider in the marine ecosystems. In this study, L. okamurae was collected from tropical coast of Sanya, and firstly described based on both detailed morph-anatomical characteristics and molecular studies of typic DNA sequences. The structure of the thalli of L. okamurae was pseudoparenchymatous construction with radially organized dimerous organizations in the crustose portion. The pseudoparenchymatous construction were composed of three parts, including 1 to 3 layers of epithelia cells which had flatten to round outermost walls, one layer of square or rectangular cells of the hypothallia and multiple layers of square or elongated rectangular peripheral cells. Palisade cells were observed, and the cells of the contiguous vegetative filaments were connected by secondary pit-connections with cell fusions absent. The carposporangial conceptacles, the spermatangial conceptacles, the bisporangial conceptacles and the tetrasporangial conceptacles were observed, and all these four kinds of conceptacles were uniporate. The spermatangial conceptacles were slightly convex and buried at shallow depths in the thalli tissues, and the carposporangial conceptacles and asexual conceptacles were protruding and conical. Phylogenetic studies based on DNA barcoding markers of 18S rDNA, COI, rbcL and psbA revealed that L. okamurae clustered with the closest relation of L. atlanticum, and formed a distinct branch. Based on the comparative anatomical features and the molecular data, the detailed description of the valid species of L. okamurae was firstly given in this study to provide theoretical basis for algae resources utilization and conservation in marine ecosystems.

Morphology of <i>Lithothamnion japonicum</i> (Hapalidiaceae, Rhodophyta): A New Record of Coralline Species from Korea

The morphology, anatomy and reproduction (tetra/bisporic and male) of Lithothamnion japonicum Foslie was studied, using holotype material and materials collected from Korea. Lithothamnion japonicum is characterized based on the presence of encrusting, warty to fruticose thallus, branched or unbranched short and cylindrical protuberances, conical shaped spermatangial conceptacles, branched (dendroid) spermatangial systems formed on floor, walls, and roof of conceptacle chamber, cylindrical shaped spermatangial conceptacle canal, 9-10 cell layered spermatangial conceptacle roof, raised tetra/bisporangial conceptacles without rims, flattened tetra/ bisporangial conceptacle pore plate, 16-50 pores on each pore plate, 6-8 rosette cells surrounded by each pore, pore canal lining filaments composed of tetra/bisporangial conceptacle roof, and buried senescent tetra/bisporangial conceptacles completely infilled with relatively large and irregularly arranged calcified sterile cells. In this study, we report a new record of Lithothamnion japonicum from Korean coasts.

Life history, growth, and pigment content of two morphological variants of Hypnea pseudomusciformis (Gigartinales, Rhodophyta)

Specimens previously described as Hypnea musciformis and Hypnea nigrescens in Brazil were shown to be morphological variants of a new species named Hypnea pseudomusciformis, which has been used for the production of carrageenan on the coast of Brazil. In this study, individuals of both morphological variants were collected in the field and cultivated in unialgal culture conditions. The life history of both variants was completed in 118 days. Tetrasporophytes produced tetrasporangia in 40 days. Released tetraspores germinated and 15 days later, an erect cylindrical axis developed from basal disk. At the age of 35 days, spermatangial conceptacles could be observed, and after 3 days of co-culture of male and female gametophytes, cystocarps could be observed, indicating the occurrence of fertilization. Finally, carpospores were released from cystocarps after 10 days, germinated and originated new tetrasporophytes in 15 days. When cultured, the morphological differences between the “musciformis” and “nigrescens” variants were attenuated and the life histories were the same. Furthermore, both morphological variants had different growth rates, but similar pigment content. These results corroborate that, for Brazil, specimens previously identified as H. musciformis and H. nigrescens are variants of H. pseudomusciformis, a highly plastic species.

Gracilaria suzannae sp. nov. (Gracilariales, Rhodophyta), a new flattened species from northeast Brazil based on morphological and molecular evidence

:A new species of Gracilaria, G. suzannae sp. nov., is described on the basis of detailed morphological, anatomical and molecular evidence from recent collections from intertidal reefs of northeastern Brazil. Diagnostic features of the new species include: tufted and tough thalli with subdichotomous, alternate to irregular branches; some branches incurved, with discrete marginal teeth, giving thalli a dentate to lacerate appearance in the upper parts; an abrupt transition of cell size between cortical and medullary regions; spermatangial conceptacles of the textorii type; and mature cystocarps with inconspicuous inner pericarp and few tubular nutritive filaments, particularly in basal portions. Universal plastid amplicon sequences of G. suzannae formed a distinct group within the genus Gracilaria, with intraspecific divergence of 0.24%. In the rbcL analysis, G. suzannae was recovered as sister to a well-supported clade containing G. occidentalis from the United States, with interspecific divergence of 1.3%. Unlike our specimens, the thallus habit of G. occidentalis is repeatedly forked, with smooth margins and rounded apices. Furthermore, G. suzannae was phylogenetically positioned close to a major clade composed of Indo-Pacific flat species with lobed, spiny or denticulate margins, all of which diverged 1.1 to 4.8% from G. suzannae. Gracilaria suzannae becomes the 16th flat species of Gracilaria reported for Brazil.

Genetic and morphological analyses of Gracilaria firma and G. changii (Gracilariaceae, Rhodophyta), the commercially important agarophytes in western Pacific.

Many studies classifying Gracilaria species for the exploitation of agarophytes and the development of the agar industry were conducted before the prevalence of molecular tools, resulting in the description of many species based solely on their morphology. Gracilaria firma and G. changii are among the commercially important agarophytes from the western Pacific; both feature branches with basal constrictions that taper toward acute apices. In this study, we contrasted the morpho-anatomical circumscriptions of the two traditionally described species with molecular data from samples that included representatives of G. changii collected from its type locality. Concerted molecular analyses using the rbcL and cox1 gene sequences, coupled with morphological observations of the collections from the western Pacific, revealed no inherent differences to support the treatment of the two entities as distinct taxa. We propose merging G. changii (a later synonym) into G. firma and recognize G. firma based on thallus branches with abrupt basal constrictions that gradually taper toward acute (or sometimes broken) apices, cystocarps consisting of small gonimoblast cells and inconspicuous multinucleate tubular nutritive cells issuing from gonimoblasts extending into the inner pericarp at the cystocarp floor, as well as deep spermatangial conceptacles of the verrucosa-type. The validation of specimens under different names as a single genetic species is useful to allow communication and knowledge transfer among groups from different fields. This study also revealed considerably low number of haplotypes and nucleotide diversity with apparent phylogeographic patterns for G. firma in the region. Populations from the Philippines and Taiwan were divergent from each other as well as from the populations from Malaysia, Thailand, Singapore and Vietnam. Establishment of baseline data on the genetic diversity of this commercially important agarophyte is relevant in the context of cultivation, as limited genetic diversity may jeopardize the potential for its genetic improvement over time.

A new flat Gracilaria: Gracilaria lantaensis sp. nov. (Gracilariales, Rhodophyta) from the Andaman coast of Thailand

:Collection of a flat red alga of the genus Gracilaria from the Andaman coast of Thailand was described as a new species, G. lantaensis sp. nov. based on detailed morphological characteristics and rbcL sequence analysis. This species typically grew intertidally on exposed mud-sand shores. It was characterized by its slender thalli with narrow-bladed branches, its smooth margin with a few brachlets and its reddish-pink color. Spermatangial conceptacles were of the textorii-type. Cystocarps were spherical and possessed numerous nutritive filaments at lateral and basal positions in the cystocarp cavity. Gracilaria lantaensis was morphologically similar to G. yamamotoi but differed in branching pattern and cystocarp structure. RbcL sequence data also indicated the genetic distinction between G. lantaensis and other species of Gracilaria. Gracilaria lantaensis was grouped with a major assemblage of Gracilaria species, and sister to some Indian Ocean species with denticulate margins, e.g. G. beckeri, G. capensis and G. denticulata.

Development of conceptacles in Amphiroa (Corallinales, Rhodophyta)

Here, we describe the development of sporangial and gametangial conceptacles for Amphiroa beauvoisii and A. vanbosseae; sporangial conceptacles only for A. misakiensis; and gametangial conceptacles only for A. cryptarthrodia and A. rigida. The descriptions are based on the observation of histological preparations obtained from 112 specimens collected from the Gulf of California, in Mexico, and the Azores archipelago of Portugal. Information on the development of the sporangial conceptacle pore and conceptacle senescence is here described and illustrated for the first time. Four development patterns were observed: two for sporangial conceptacles; one for spermatangial conceptacles; and one for carposporangial conceptacles. The phases of development of the sporangial conceptacle were found to be useful in delimiting species within the genus. Based on the sporangium location on the cavity floor and the pore canal anatomy, the species A. beauvoisii, A. misakiensis and A. vanbosseae can be distinguished from each other.

Molecular evidence confirms the parasite Congracilaria babae (Gracilariaceae, Rhodophyta) from Malaysia

A phylogenetic study of two parasites found on the common host species Gracilaria salicornia from Japan and Malaysia based on nuclear, plastid, and mitochondrial molecular markers was conducted. The Japanese and Malaysian parasites were placed in the same cluster in the nuclear phylogenies inferred from the LSU rRNA gene and ITS region, supporting the monophyly of these parasites despite the slight anatomical variations observed. In addition to the molecular analyses, shared morphological and reproductive features including the lack of rhizoids, similar coloration to hosts, and the presence of deep spermatangial conceptacles supported the inclusion of both the Japanese and Malaysian parasites in Congracilaria babae. Phylogenetic analyses based on ITS sequences indicated that C. babae most likely evolved directly from its current host species, G. salicornia. C. babae was shown to be a member of Gracilaria sensu stricto along with its host. C. babae growing on G. salicornia is characterized by having plastid rbcL and mitochondrial cox1 gene sequences identical to those of its host, whereas the nuclear LSU rRNA gene and ITS region sequences are different from those of its host.

Gracilaria viridis sp. nov. (Gracilariales, Rhodophyta): a new red algal species from the Mediterranean Sea

Sfriso A., Wolf M.A., Sciuto K., Morabito M., Andreoli C. and Moro I. 2013. Gracilaria viridis sp. nov. (Gracilariales, Rhodophyta): a new red algal species from the Mediterranean Sea. Phycologia 52: 65–73. DOI: 10.2216/12-007.1We characterized a new Gracilaria species from the Venice Lagoon, Italy, using molecular analyses based on the plastid large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) and the intergenic RuBisCO spacer (rbcL-rbcS), combined with morphology data. This new entity was recorded on the artificial substrata of the Venice Gulf from March to July, adding to 12 Gracilaria taxa already recorded in the Mediterranean and Adriatic seas. Thalli exhibited a green-yellowish pigmentation with pink shades, and there was dense branching in the distal portions. Tetrasporangia were scattered on thallus cortex and distributed mostly on short, stipitate branchlets. The inner pericarp was connected to the gonimoblast by tubular nutritive cells. The male gametophytic plants formed round-elliptical spermatangial verrucosa-type conceptacles. This species grew attached on artificial rocky substrata of the low midlittoral and upper sublittoral zone in spring and early summer. Molecular analyses based on the plastid-encoded rbcL gene showed a 99.66% nucleotide identity with another Gracilaria sp. from southern Sicily. We compared our rbcL-rbcS spacer sequences with those of two cryptic species, and the phylogenetic analyses confirmed that the Venice populations were a new species. We suggested that the discovery of this new species was not due to an extra-Mediterranean introduction but the consequence of its misidentification as Gracilaria gracilis, which has a similar gross morphology.

Characterization of Gracilaria vieillardii (Gracilariaceae, Rhodophyta) and molecular phylogeny of foliose species from the western Pacific Ocean, including a description of G. taiwanensis sp. nov.

Lin S.-M., Liu L.-C. and Payri C. 2012. Characterization of Gracilaria vieillardii (Gracilariaceae, Rhodophyta) and molecular phylogeny of foliose species from the western Pacific Ocean, including a description of G. taiwanensis sp. nov. Phycologia 51: 421–431. DOI: 10.2216/11-90.1Gracilaria vieillardii has been widely reported from the western Pacific Ocean; however, these records remained provisional due to the absence of morphological details for material from the type locality, New Caledonia. To clarify the taxonomic position of G. ‘vieillardii’ from Taiwan and the interspecific relationships of the foliose Gracilaria species from the western Pacific Ocean, we used rbcL sequences and inferred their molecular phylogeny along with that of other foliose species from around the world. Foliose species with textorii-type spermatangial conceptacles, collected from the western Pacific Ocean, were analyzed here along with foliose species from South Africa. These formed a natural assemblage. In contrast, those foliose species with textorii-type spermatangial conceptacles, which were collected from the tropical Atlantic Ocean, did not form a monophyletic clade. We described Gracilaria taiwanensis sp. nov., based upon a foliose species with marginal teeth, that was previously recorded from Taiwan as G. vieillardii. Our molecular analyses indicated that G. taiwanensis was sister to the clade of G. vieillardii from the type locality, New Caledonia; however, they differed by 28 base pairs among 1390 aligned nucleotides of the rbcL gene. Gracilaria taiwanensis was characterized by its palmate, prostrate thallus and thicker cystocarp floor (180–300 µm thick). In contrast, G. vieillardii possessed bushy, slightly prostrate thalli, and the cystocarp floor was not as thick (100–150 µm thick).

Some new recorded species for the family Gracilariaceae (Rhodophyta) for the algae of Vietnam

On the basis of the taxonomic criteria utilized in the family (Gracilariaceae) which was presented by Abbott et al. (1985): species identification must be based on the difference of gross morphology and combinated with reproductive anatomical details as spermatangial conceptacles, cystocarps, the presence of nutritive filaments, the shapes of cells that make up the pericarps. After re-examination of more than 600 specimens of Gracilariaceae previously collected by the others and newly collected by author along the coast of Vietnam, which are deposited in the herbarium at the Institute of Oceanography Nhatrang (ION), Nhatrang Institute of Technology Research and Application (NITRA) and Institute of Marine Environment and Resource Haiphong (IMER), There were 20 species identified for Vietnamese Gracilariaceae, of those, five species are new records for the red alga of Vietnam, namely Gracilaria cuneifolia (Okamura) Lee & Kurogi, Gracilaria rubra Chang & Xia, Gracilaria yamamotoi Zhang & Xia, Hydropuntia divergens (Xia & Abbott) Wynne, Gracilariopsis nhatrangensis Le & Lin. Nomenclature, distribution, biology and ecology of all species were also provided.

MESOPHYLLUM SPHAERICUM SP. NOV. (CORALLINALES, RHODOPHYTA): A NEW MAËRL-FORMING SPECIES FROM THE NORTHEAST ATLANTIC(1).

Mesophyllum sphaericum sp. nov. is described based on spherical maërl individuals (up to 10 cm) collected in a shallow subtidal maërl bed in Galicia (NW Spain). The thalli of these specimens are radially organized, composed of arching tiers of compact medullary filaments. Epithallial cells have flattened to rounded outermost walls, and they occur in a single layer. Subepithallial initials are as long as, or longer than the daughter cells that subtend them. Cell fusions are abundant. Multiporate asexual conceptacles are protruding, mound-like with a flattened pore plate, lacking a peripheral raised rim. Filaments lining the pore canal and the conceptacle roof are composed of five to six cells with straight elongate and narrow cells at their base. Carposporangial conceptacles are uniporate, protruding, and conical. Spermatangial conceptacles were not observed. Molecular results placed M. sphaericum near to M. erubescens, but M. sphaericum is anatomically close to M. canariense. The examination of the holotype and herbarium specimens of M. canariense indicated that both species have pore canal filaments with elongate basal cells, but they differ in number of cells (five to six in M. sphaericum vs. four in M. canariense). Based on the character of pore canal filaments, M. canariense shows similarities with M. erubescens (three to five celled). The outermost walls of epithallial cells of M. canariense are flared compared to the round to flattened ones of M. erubescens, the latter being widely accepted for the genus Mesophyllum. The addition of M. sphaericum as new maërl-forming species suggests that European maërl beds are more biodiverse than previously understood.

REVISION OF THE MASTOPHOROIDEAE (CORALLINALES, RHODOPHYTA) AND POLYPHYLY IN NONGENICULATE SPECIES WIDELY DISTRIBUTED ON PACIFIC CORAL REEFS1.

The subfamily Mastophoroideae (Corallinaceae, Rhodophyta) is characterized by species possessing nongeniculate, uniporate tetrasporangial conceptacles without apical plugs, the presence of cell fusions, and the absence of secondary pit connections. However, molecular phylogenetic studies not including the type genus Mastophora indicated that the Mastophoroideae was polyphyletic. Our molecular phylogenetic analysis of the subfamily including the type genus using DNA sequences of SSU rDNA and plastid-encoded gene of PSII reaction center protein D1 (psbA) revealed that Mastophora formed a robust clade only with Metamastophora. The other mastophoroid genera were divided into six lineages within the family Corallinaceae. Five supported lineages-(i) Pneophyllum; (ii) Hydrolithon gardineri (Foslie) Verheij et Prud'homme, Hydrolithon onkodes (Heydr.) Penrose et Woelk., and Hydrolithon pachydermum (Foslie) J. C. Bailey, J. E. Gabel et Freshwater; (iii) Hydrolithon reinboldii (Weber Bosse et Foslie) Foslie; (iv) Spongites; and (v) Neogoniolithon-were clearly distinguished by the combination of characters including the presence or absence of palisade cells and trichocytes in large, tightly packed horizontal fields and features of tetrasporangial and spermatangial conceptacles. Therefore, we amend the Mastophoroideae to be limited to Mastophora and Metamastophora with a thin thallus with basal filaments comprised of palisade cells, tetrasporangial conceptacles formed by filaments peripheral to fertile areas, and spermatangia derived only from the floor of male conceptacles. This emendation supports Setchell's (1943) original definition of the Mastophoroideae as having thin thalli. We also propose the establishment of three new subfamilies, Hydrolithoideae subfam. nov. including Hydrolithon, Porolithoideae subfam. nov. including the resurrected genus Porolithon, and Neogoniolithoideae subfam. nov. including Neogoniolithon. Taxonomic revisions of Pneophyllum and Spongites were not made because we did not examine their type species.

Gracilaria, subgénero Textoriella (Gracilariaceae, Rhodophyta) en el golfo de México y el Caribe mexicano

Four species of Gracilaria (Gracilariaceae, Rhodophyta) with textorii-type spermatangial conceptacles (subgenus Textoriella Yamamoto) are recorded for the Gulf of Mexico and the Mexican Caribbean: Gracilaria blodgettii, G. cervicornis, G. mammillaris, and G. tikvahiae. The general distribution of the subgenus for Central America, both Pacific and Atlantic, displays a disjunct pattern explainable based on the geologic vicariant events that interrupted the connection between Pacific and Atlantic at the Isthmuses of Panama (closed 3.1-2.8 million years ago), and Tehuantepec (southern Mexico, closed 4-3.5 million years ago). Gracilaria cuneata/G. crispata, and G. mammillaris (G. hayi)/G. veleroae are 2 pairs of sibling species, or sister taxa, that diverged as a result of the final emergence of the Isthmus, and of the same age as the Central American Isthmus itself.

Taxonomy and phylogeny of flattened species of Gracilaria (Gracilariceae, Rhodophyta) from Korea based on morphology and protein-coding plastid rbcL and psbA sequences

M.-S. Kim, E.C. Yang and S.M. Boo. 2006. Taxonomy and phylogeny of flattened species of Gracilaria (Gracilariceae, Rhodophyta) from Korea based on morphology and protein-coding plastid rbcL and psbA sequences. Phycologia 45: 520–528. DOI: 10.2216/05-38.1Despite extensive studies on cylindrical Gracilaria species, the taxonomy and phylogeny of the flattened species of the genus has received little attention. We studied the morphology and molecular phylogeny of three flattened species of Gracilaria, hitherto reported from Korea. Gracilaria textorii is characterized by having a wider blade relative to other species, margins entire or proliferous, coriaceous thallus texture, one to three large cells in the medulla, and shallow male conceptacles. Gracilaria cuneifolia is membranous in texture, and has shallow spermatangial conceptacles (approximately 10 µm in depth). We generated psbA and rbcL sequences from 32 specimens of G. textorii, G. cuneifolia and its putative relatives in Korea and surrounding waters. Twenty-three specimens of G. textorii from Korea, including two from Japan, were almost identical in both rbcL and psbA regions, except for some specimens that were different by one to four nucleotides. Three specimens of G. cuneifolia were identical in both rbcL and psbA. However, we found no evidence for the occurrence of G. incurvata in Korea. In all analyses of rbcL, psbA, and rbcL + psbA data sets, G. textorii was determined to be a unique species, with G. incurvata from Japan as a sister species. Gracilaria cuneifolia is more closely related to the G. tikvahiae group from the Atlantic than G. textorii and G. incurvata.

Gracilaria vermiculophylla: A western Pacific species of Gracilariaceae (Rhodophyta) first recorded from the eastern Pacific

SUMMARY We report Gracilaria vermiculophylla (Ohmi) Papenfuss from the Pacific coast of North America based on a morphoanatomical revision and comparison of sequences of the nuclear gene coding for the small subunit of ribosomal RNA and the internal transcribed spacers of populations from Baja California, Mexico and Hiroshima, Japan. It is the first convincing report of this species out of its center of distribution in western north Pacific, where it has been considered as a synonym of former ‘ G. verrucosa ’ records. G. vermiculophylla also occurs in central California as indicated by internal transcribed spacer sequences of a previously unknown Gracilaria Greville material. In the northeastern Pacific G. vermiculophylla is characterized by a robust somewhat vermiform, well-branched cylindrical thallus, with gradual cell size transition from cortex to medulla, deep spermatangial conceptacles, regular chains of carposporangia and carposporangial initials, downwardly oriented tubular nutritive cells, but rarely with upwardly oriented tubular nutritive cells. In some features of its cystocarp anatomy G. vermiculophylla is related to Gracilariopsis E. Y. Dawson or Hydropuntia Montagne and it is a relevant species for discussions about Gracilariaceae genera.

Histórico de vida de espécimens selvagens e variantes cromáticas de Gracilaria birdiae (Gracilariales, Rhodophyta)

(Gracilariales, Rhodophyta) e uma macroalga marinha de coloracao vermelha (vm) comum na costa Nordeste do Brasil e amplamente coletada para a extracao de agar. O objetivo deste estudo foi completar o historico de vida de especimens selvagens (coloracao vermelha) e variantes cromaticas. Duas variantes foram isoladas, alem dos especimens selvagens coletados na praia de Paracuru, Ceara: i, marrom-esverdeada (me), encontrada em uma populacao natural da praia de Paracuru; e ii, verde (vd), obtida espontaneamente in vitro a partir de um ramo tetrasporofitico. As condicoes gerais de cultivo tanto para gametofitos quanto para tetrasporofitos foram: meio de cultura von Stosch 25%; fotoperiodo 14L:10E (luz: escuro); irradiância 100 µm.m-2.s-1 e aeracao a cada 30 min. Tetrasporofitos das tres coloracoes e gametofitos verdes foram cultivados tambem em 10L:14E. O historico de vida foi completado in vitro em 498 (vm), 523 (me) e 861 (vd) dias, mostrando-se do tipo Polysiphonia. Tetrasporofitos produziram tetrasporos apenas em fotoperiodo 10L:14E. Gametofitos femininos verdes desenvolveram cistocarpos apenas em fotoperiodo 14L:10E. No entanto, a diferenciacao de conceptaculos do tipo verrucosa em gametofitos masculinos verdes e a liberacao de espermacios ocorreu em ambos os fotoperiodos. Gametofitos masculinos vermelhos apresentaram conceptaculos espermatangiais do tipo henriquesiana, enquanto gametofitos masculinos marrom-esverdeados apresentaram os tipos verrucosa e henriquesiana. Nao foram verificadas diferencas quanto ao habito de especimens de uma mesma coloracao, independentemente do estadio reprodutivo analisado. Verificou-se em todos os tetrasporofitos a germinacao de tetrasporos in situ.

New record of Gracilaria firma Chang et Xia (Rhodophyta) from Okinawa, Japan

SUMMARY Gracilaria firma Chang et Xia is newly recorded for Japan, where it grows at Okinawa Island, on the Pacific coast of the Ryukyu Archipelago. This species is characterized by (i) cylindrical axes with a discoid holdfast; (ii) branches and branchlets constricted at their bases; (iii) acute to blunt apices; (iv) colour greenish-brown to yellowish-brown; (v) scarce traversing filament between the dense gonimoblast and the pericarp; and (vi) deep, pot-shaped Verrucosa-type spermatangial conceptacles. The Japanese specimens agree well with previously known South-East Asian specimens as well as the original description of G. firma from south China.

A taxonomic study on two Japanese species of Gracilaria: Gracilaria shimodensis sp. nov. and Gracilaria blodgettii (Gracilariales, Rhodophyta)

SUMMARY Japanese populations of the red alga Gracilaria blodgettii Harvey (Gracilariaceae, Gracilariales) were reinvesti-gated by morphological and cultural studies. Plants of populations growing on the Pacific coast of central Japan (Shizuoka and Chiba Prefectures) produce deep pot-shaped, Verrucosa-type spermatangial conceptacles and are entirely different from genuine G. blodgettii from the Caribbean Sea that bears shallowly depressed Textorii-type spermatangial conceptacles. However, plants from a population in southern Japan (Okinawa Prefecture) agree well with the circumscription of G. blodgettii, including the Textorii-type spermatangial conceptacles. The alga that produces the deep pot-shaped, Verrucosa-type spermatangial conceptacles and is distributed on the Pacific coast of central Japan is distinguished from all known species of Gracilaria by the following set of features in addition to the spermatangial feature and is described as Gracilaria shimodensis Terada et Yamamoto, sp. nov.: (i) remarkable constrictions at the bases of branches and branchlets; (ii) large gonimoblast cells; (iii) abundant traversing filaments; and (iv) a thick pericarp which consists of 8–10 layers of cells.