CERAMIUM INKYUII SP. NOV. (CERAMIACEAE,RHODOPHYTA) FROM KOREA: A NEW SPECIES BASED ON MORPHOLOGICAL AND MOLECULAR EVIDENCE1

Ceramium inkyuii sp. nov. is newly described based on samples collected from the east coast of Korea and compared with similar species such as C. paniculatum and C. tenerrimum. The new species is characterized by pseudo‐dichotomously branched thalli with a twist in the upper part, a single row of spines on the abaxial side, strongly inrolled apices, and the presence of gland cells. In contrast, C. paniculatum has alternate branches and lacks gland cells, and C. tenerrimum is spineless and also lacks gland cells. Ceramium inkyuii was observed to be an annual species producing tetrasporangia in the spring to summer and cystocarps in the fall. Plastid‐encoded rbcL and nuclear small subunit (SSU) rDNA sequences were determined in four samples of C. inkyuii from different locations and six samples of four putative relatives. All four C. inkyuii replicates from three different locations had identical sequences of each gene, and the interspecific sequence divergences were enough to warrant its natural entity. The phylogenies of the rbcL and SSU rDNA sequences also indicate the monophyly of C. inkyuii. The spinous C. inkyuii was more closely related to the spineless C. tenerrimum than to the spinous C. paniculatum.     

MORPHOLOGY AND SYSTEMATICS OF SCIUROTHAMNION STEGENGAE GEN. ET SP. NOV. (CERAMIACEAE,RHODOPHYTA) FROM THE INDO‐PACIFIC1

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.     

MOLECULAR SYSTEMATICS OF CERAMIUM AND CENTROCERAS (CERAMIACEAE,RHODOPHYTA) FROM BRAZIL1

Morphological investigations identified 11 Ceramium Roth species, of the 18 previously reported from Brazil. Phylogenetic analyses of sequences of the chloroplast‐encoded rbcL gene confirmed the presence of seven of these species. Three other species are reported from Brazil for the first time. Ceramium affine Setchell & Gardner and C. filicula Harvey ex Womersley were previously known only from the Pacific Ocean (Mexico and Australia, respectively). A new species, C. fujianum Barros‐Barreto et Maggs sp. nov., is described here. Its general habit is similar to that of C. strictum sensu Harvey from Europe but it has one less periaxial cell than C. strictum; its cortical filament arrangement is closest to C. deslongchampsii Chauvin ex Duby, also from Europe, but whorled tetrasporangia partially covered by cortical cells differ strikingly from the naked protruding tetrasporangia of C. deslongchampsii. Ceramium species in which each periaxial cell cuts off transversely only a single basipetal cell formed a robust clade. The genus Ceramium as represented in Brazil is not monophyletic with respect to Centroceras Kützing and Corallophila Weber‐van Bosse; Ceramium nitens, which has axial cells completely covered by rounded cortical cells formed by acropetal and basipetal filaments, did not group with any Ceramium clade but was weakly allied to a species of Corallophila. All three Brazilian Centroceras sequences were attributed to a single species, C. clavulatum.     

SYSTEMATICS OF THE DELESSERIACEAE (CERAMIALES, RHODOPHYTA) BASED ON LARGE SUBUNIT rDNA AND rbcL SEQUENCES, INCLUDING THE PHYCODRYOIDEAE, SUBFAM. NOV.

The present classification of the Delesseriaceae retains the essential features of Kylin's system, which recognizes two subfamilies Delesserioideae and Nitophylloideae and a series of “groups” or tribes. In this study we test the Kylin system based on phylogenetic parsimony and distance analyses inferred from two molecular data sets and morphological evidence. A set of 72 delesseriacean and 7 additional taxa in the order Ceramiales was sequenced in the large subunit rDNA and rbcL analyses. Three large clades were identified in both the separate and combined data sets, one of which corresponds to the Delesserioideae, one to a narrowly circumscribed Nitophylloideae, and one to the Phycodryoideae, subfam. nov., comprising the remainder of the Nitophylloideae sensu Kylin. Two additional trees inferred from rbcL sequences are included to provide broader coverage of relationships among some Delesserioideae and Phycodryoideae. Belonging to the Delesserioideae are the Caloglosseae with Caloglossa; an expanded Hemineureae that includes Hemineura, Patulophycus, Marionella, Laingia, Botryocarpa, and Pseudophycodrys; the Delesserieae with Delesseria and Membranoptera; the Apoglosseae with Apoglossum and a group of southern hemisphere species presently placed in Delesseria that belong in Paraglossum; the Hypoglosseae with Hypoglossum, Branchioglossum, Zellera, and Bartoniella; and the Grinnellieae with Grinnellia. The revised Nitophylloideae contains the Nitophylleae with Nitophyllum, Valeriemaya, Polyneuropsis, and Calonitophyllum and the Martensieae with Opephyllum and Martensia. A new subfamily, Phycodryoideae, is proposed to include the Phycodryeae with Phycodrys, Polyneura, Nienburgia, Cladodonta, Heterodoxia, and Womersleya; the Cryptopleureae with Cryptopleura, Hymenena, Acrosorium, and Botryoglossum; the Myriogrammeae with Myriogramme and Haraldiophyllum; and the Schizoserideae with Schizoseris, Neuroglossum, Drachiella, Abroteia, and species from South America placed in Platyclinia. This research promotes the correlation of molecular and morphological phylogenies.     

PHYLOGENETIC RELATIONSHIPS AMONG LINEAGES OF THE CERAMIACEAE (CERAMIALES,RHODOPHYTA) BASED ON NUCLEAR SMALL SUBUNIT rDNA SEQUENCE DATA1

Phylogenetic relationships among 69 species of the Ceramiales (51 Ceramiaceae, six Dasyaceae, seven Delesseriaceae, and five Rhodomelaceae) were determined based on nuclear SSU rDNA sequence data. We resolved five strongly supported but divergent lineages among the included Ceramiaceae: (i) the genus Inkyuleea, which weakly joins other orders of the Rhodymeniophycidae rather than the Ceramiales in our analyses; (ii) the tribe Spyridieae, which is sister to the remainder of the included ceramialean taxa; (iii) the subfamily Ceramioideae, weakly including the tribe Warrenieae; (iv) the subfamily Callithamnioideae; and (v) the subfamily Compsothamnioideae, which emerges as sister to the Dasyaceae/Delesseriaceae/Rhodomelaceae complex, thus rendering the Ceramiaceae sensu lato unequivocally paraphyletic, as has been argued separately on anatomical grounds by Kylin and Hommersand. Our data support a restricted concept of the Ceramiaceae that includes only one of the five lineages (Ceramioideae) that we have resolved. In addition to failing to ally with the Ceramiales in our molecular analyses, species of Inkyuleea differ substantially from other Ceramiaceae sensu lato in details of pre‐ and postfertilization development. The genus Inkyuleea is here assigned to the Inkyuleeaceae fam. nov., which we provisionally retain in the Ceramiales. Species of Spyridia also differ from the remaining Ceramiaceae in their postfertilization development, and, in light of our molecular data, the genus Spyridia is assigned to the Spyridiaceae. The Callithamnioideae is strongly monophyletic (100% in all analyses), which, in combination with key anatomical differences, supports elevation to family status for this lineage as the Callithamniaceae. Similarly, the Compsothamnioideae is solidly monophyletic in our molecular trees and has a unique suite of defining anatomical characters that supports family status for a complex that we consider to include the tribes Compsothamnieae, Dasyphileae, Griffithsieae, Monosporeae, Ptiloteae, Spermothamnieae, Sphondylothamnieae, Spongoclonieae, and Wrangelieae, for which the reinstated family name Wrangeliaceae is available.     

NEW INSIGHTS IN THE TAXONOMY OF THE CERAMIUM SINICOLA COMPLEX: RESURRECTION OF CERAMIUM INTERRUPTUM (CERAMIACEAE,RHODOPHYTA)1

Phylogenetic relationships of the Ceramium sinicola complex (C. interruptum and C. sinicola) including C. codicola were studied using nucleotide sequences of rbcL and small subunit rDNA, and the RUBISCO spacer was used for sequence comparison of each species. A reassessment of the taxonomic rank and the evolutionary trend within the complex was inferred from a comparative morphological study and molecular data sets based on 11 samples from eight populations from the Pacific coast of the United States and Mexico. Intraspecific relationships were poorly resolved, but the resurrection of C. interruptum as a distinct species was strongly supported by both morphological and molecular data. Ceramium interruptum is distinguished by the combination of the following features: thalli uncorticated at the first internode above the dichotomy, presence of four corticating filaments, 7–11 segments between branching points, rhizoids digitate, and epiphytic on a variety of hosts. Our molecular analyses show that C. sinicola is the sister group to C. codicola, and C. interruptum is basal to them. These phylogenetic relationships allowed for an assessment of the trend in the evolution of cortication pattern and attachment mode to the host.     

MOLECULAR PHYLOGENY,ULTRASTRUCTURE, AND TAXONOMIC REVISION OF CHLOROGONIUM (CHLOROPHYTA): EMENDATION OF CHLOROGONIUM AND DESCRIPTION OF GUNGNIR GEN. NOV. AND RUSALKA GEN. NOV.1

We examined the molecular phylogeny and ultrastructure of Chlorogonium and related species to establish the natural taxonomy at the generic level. Phylogenetic analyses of 18S rRNA and RUBISCO LSU (rbcL) gene sequences revealed two separate clades of Chlorogonium from which Chlorogonium (Cg.) fusiforme Matv. was robustly separated. One clade comprised Cg. neglectum Pascher and Cg. kasakii Nozaki, whereas the other clade included the type species Cg. euchlorum (Ehrenb.) Ehrenb., Cg. elongatum (P. A. Dang.) Francé, and Cg. capillatum Nozaki, M. Watanabe et Aizawa. On the basis of unique ultrastructural characteristics, we described Gungnir Nakada gen. nov. comprising three species: G. neglectum (Pascher) Nakada comb. nov., G. mantoniae (H. Ettl) Nakada comb. nov., and G. kasakii (Nozaki) Nakada comb. nov. We also emended Chlorogonium as a monophyletic genus composed of Cg. euchlorum, Cg. elongatum, and Cg. capillatum. Because Cg. fusiforme was distinguished from the redefined Chlorogonium and Gungnir by the structure of its starch plate, which is associated with pyrenoids, we reclassified this species as Rusalka fusiformis (Matv.) Nakada gen. et comb. nov.     

MORPHOLOGY AND TAXONOMY OF MERISTIELLA GEN. NOV. (SOLIERIACEAE,RHODOPHYTA) 1

Eucheuma acanthocladum (Harvey) J. Agardh, E. gelidium (J Agardh) J. Agardh, E. echinocarpum Areschoug and E. schrammii(P. et H. Crouan) J. Agardh from the tropical and warm temperate waters of the western Atlantic Ocean and Caribbean Sea are transferred to a new genus, Meristiella. Meristiella exhibits the following Unique combination of characters among genera in the Solieriaceae: (1) rotated periaxial cells, (2) a loosely filamentous medulla. (3) an auxiliary cell complex, (4) Single and twin connecting filaments and (5) spinose cystocarps composed of a central, small-celled placentum, based on its reproductive features, Meristiella. is assigned to the tribe Agardhielleae. Culture experiments and herbarium studies provide evidence that E, gelidium and E. acantghocladum are conspecific. Lectotypes are designated for the included species.     

A NEW AGAROPHYTE SPECIES,GELIDIUM EUCORNEUM SP. NOV. (GELIDIALES,RHODOPHYTA), BASED ON MOLECULAR AND MORPHOLOGICAL DATA1

Gelidium is an economically and ecologically important agar‐producing genus. Although the taxonomy of Gelidium has been the focus of many published studies, there is still a need to reevaluate species‐level diversity. Herein, we describe Gelidium eucorneum sp. nov. based on specimens collected off Geojedo on the southern coast of Korea. G. eucorneum is distinguished by cartilaginous thalli with brush‐like haptera, rhizoidal filaments concentrated in the medulla, and globose cytocarps that are horned with multiple determinate branchlets. The species occurs in wave‐exposed intertidal sites, sometimes in association with other mat‐forming algae. Phylogenetic analyses (rbcL, psaA, and cox1) reveal that G. eucorneum is unique and clearly distinct from other species of the genus. The clade containing Gelidium vagum and Acanthopeltis longiramulosa was resolved as a sister group to G. eucorneum. We suggest that the diverse morphologies of G. eucorneum, G. vagum, and Acanthopeltis developed from a common ancestor in East Asian waters. This study shows that even in well‐studied areas, more agarophyte species are to be added to the world inventory of red algae.     

STRUCTURE AND REPRODUCTION OF AMANSIA AND MELANAMANSIA GEN. NOV. (RHODOPHYTA,RHODOMELACEAE) ON THE SOUTHEASTERN AFRICAN COAST1

Four species of Amansia Lamouroux were initially found in Natal. More Complete studies on these species revealed a new genus, Melanamansia, Which is described on the basis of presence of two dorsal pseudopericentral cells in two new species from Natal (M. seagriefii sp. nov. & M. fimbrifolia sp. nov.) in addition to other structural characters and features of pigmentation and reproduction. Pseudopericentral cells are not present in the type species of Amansia, A. multifida Lamouroux. The other two species of Amansia occurring in Natal, A. glomerata C. Agardh & A. loriformis sp. nov., have characters similar to the type species. Comparison of species from other regions of the world has shown that eight additional species, previously assigned to Amansia, belong to the new genus.     

NEW GENERA AND SPECIES OF CERAMIACEAE (RHODOPHYTA) FROM THE SOUTHEASTERN UNITED STATES1

Five Ceramiaceae (Rhodophyta) are reported from the offshore waters of the southeastern, warm temperate coast of the United States. These include two new monotypic genera, Calliclavula trifurcate Schneider in the Griffithsieae and Nwynea grandispora Searles in the Sphondylothamnieae, and three new species, Callithamniella silvae Searles, Ptilothamnion occidentale Searles, and Lejolisia exposita Schneider et Searles.     

DEUCALION GEN. NOV. AND ANISOSCHIZUS GEN. NOV. (CERAMIACEAE,CERAMIALES), TWO NEW PROPAGULE-FORMING RED ALGAE FROM SOUTHERN AUSTRALIA1

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.     

DICROGLOSSUM CRISPATULUM GEN. ET COMB. NOV. FROM WESTERN AUSTRALIA,REPRESENTING A NEW TRIBE WITHIN THE DELESSERIACEAE (RHODOPHYTA)1

Dicroglossum gen. nov. (Delesseriaceae, Ceramiales) is a monotypic genus based on Delesseria crispatula, a species originally described by Harvey for plants collected from southwestern Western Australia. Distinctive features of the new genus include exogenous indeterminate branches; growth by means of a single transversely dividing, apical cell; absence of intercalary divisions in the primary, secondary, and tertiary cell rows; lateral pericentral cells not transversely divided; not all cells of the secondary cell rows producing tertiary cells rows; all tertiary initials reaching the thallus margin; midrib present but lateral nerves absent; determinate lateral bladelets arising endogenously; blades monostromatic, except, at the midrib; carpogonial branches restricted to primary cell rows, on both surfaces of unmodified blades; procarps produced on both blade surfaces, each procarp consisting of a supporting cell that bears two four-celled carpogonial branches and one sterile-cell group of three to four cells; and tetrasporangia borne in two layers, separated by a central row of sterile cells. The combination of exogenous indeterminate branching and bicarpogonial procarps is considered to warrant the recognition of a new tribe, the Dicroglosseae, within the subfamily Delesserioideae.     

PROPOSAL OF THE EUPTILOTEAE HOMMERSAND ET FREDERICQ,TRIB. NOV. AND TRANSFER OF SOME SOUTHERN HEMISPHERE PTILOTEAE TO THE CALLITHAMNIEAE (CERAMIACEAE,RHODOPHYTA)1

Morphological and molecular studies demonstrate that the tribe Ptiloteae (Ceramiaceae, Ceramiales) is polyphyletic. The Ptiloteae, sensu stricto, occur only in the Northern Hemisphere and all Southern Hemisphere representatives belong in other tribes. Three genera (Euptilota, Seirospora, and Sciurothamnion) are transferred to the Euptiloteae Hommersand et Fredericq, trib. nov., and the Callithamnieae is revised to include three Ptilota‐like genera, Georgiella, Falklandiella, and Diapse, and two new genera. Heteroptilon Hommersand, gen. nov. is erected to receive Euptilota pappeana Kützing 1849 and Aglaothamnion rigidulum De Clerck, Bolton, Anderson et Coppejans 2004 from South Africa, and Aristoptilon Hommersand et W. A. Nelson, gen. nov. is established to receive Euptilota mooreana Lindauer 1949 from New Zealand. The principal difference between the Euptiloteae and the Callithamnieae is seen in the earliest stages after fertilization. The fertilized carpogonium enlarges and forms a pair of tube‐like protuberances directed toward the auxiliary cells that are cut off as connecting cells in the Euptiloteae, whereas in the Callithamnieae the carpogonium usually divides into two cells, each of which cuts off a small connecting cell that fuses with an adjacent enlarging auxiliary cell. Nuclei are terminal in spermatangia of the Euptiloteae, subtended by mucilaginous vesicles, and are medial in the Callithamnieae situated between apical and basal vesicles. The Euptiloteae and Callithamnieae (including the Ptilota‐like members) are each strongly supported in maximum‐likelihood tree topologies resulting from analyses of combined 18S rDNA, 28S rDNA, 16S rDNA, and rbcL data sets. Their sister relationship is also well supported.     

AUGOPHYLLUM,A NEW GENUS OF THE DELESSERIACEAE (RHODOPHYTA) BASED ON rbcL SEQUENCE ANALYSIS AND CYSTOCARP DEVELOPMENT1

A new genus, Augophyllum Lin, Fredericq et Hommersand gen. nov. related to Nitophyllum, tribe Nitophylleae, subfam. Nitophylloideae of the Delesseriaceae, is established to contain the type species Augophyllum wysorii Lin, Fredericq et Hommersand sp. nov. from Caribbean Panama; Augophyllum kentingii Lin, Fredericq et Hommersand sp. nov. from Taiwan; Augophyllum marginifructum (R. E. Norris et Wynne) Lin, Fredericq et Hommersand comb. nov. (Myriogramme marginifructa R. E. Norris et Wynne 1987) from South Africa, Tanzania, and the Sultanate of Oman; and Augophyllum delicatum (Millar) Lin, Fredericq et Hommersand comb. nov. (Nitophyllum delicatum Millar 1990 ) from southeastern Australia. Like Nitophyllum, Augophyllum is characterized by a diffuse meristematic region, the absence of macro‐ and microscopic veins, procarps consisting of a supporting cell bearing a slightly curved four‐celled carpogonial branch flanked laterally by a cover cell and a sterile cell, a branched multicellular sterile group after fertilization, absence of cell fusions between gonimoblast cells, and tetrasporangia transformed from multinucleate surface cells. Augophyllum differs from Nitophyllum by the blades becoming polystromatic inside the margins, often with a stipitate cylindrical base, the possession of aggregated discoid plastids neither linked by fine strands nor forming bead‐like branched chains, spermatangia and procarps initiated at the margins of blades, not diffuse, and a cystocarp composed of densely branched gonimoblast filaments borne on a conspicuous persistent auxiliary cell with an enlarged nucleus. Analyses of the rbcL gene support the separation of Augophyllum from Nitophyllum. An investigation of species attributed to Nitophyllum around the world is expected to reveal other taxa referable to Augophyllum.     

TAXONOMIC STUDY OF TWO NEW GENERA OF FUSIFORM GREEN FLAGELLATES,TABRIS GEN. NOV. AND HAMAKKO GEN. NOV. (VOLVOCALES,CHLOROPHYCEAE)1

On the basis of LM, we isolated strains of two species of fusiform green flagellates that could be assigned to former Chlorogonium (Cg.) Ehrenb. One species, “Cg.”heimii Bourr., lacked a pyrenoid in its vegetative cells and required organic compounds for growth. The other was similar to Cg. elongatum (P. A. Dang.) Francé and “Cg.”acus Nayal, but with slightly smaller vegetative cells. Their molecular phylogeny was also studied based on combined 18S rRNA, RUBISCO LSU (rbcL), and P700 chl a‐apoprotein A2 (psaB) gene sequences. Both species were separated from Chlorogonium emend., Gungnir Nakada and Rusalka Nakada, which were formerly assigned to Chlorogonium. They were accordingly assigned to new genera, Tabris Nakada gen. nov. and Hamakko (Hk.) Nakada gen. nov. as T. heimii (Bourr.) Nakada comb. nov. and Hk. caudatus Nakada sp. nov., respectively. Tabris is differentiated from other genera of fusiform green flagellates by its vegetative cells, which only have two apical contractile vacuoles and lack a pyrenoid in the chloroplast. Hamakko, on the other hand, is distinguishable by the fact that its pyrenoids in vegetative cells are penetrated by flattened thylakoid lamellae.     

A MORPHOLOGICAL STUDY OF HOMMERSANDIA MAXIMICARPA GEN. ET SP. NOV. (KALLYMENIACEAE,RHODOPHYTA) FROM THE NORTH PACIFIC1

A new foliose red alga, common subtidally from British Columbia to the Aleutian Islands, is described and given the name Hommersandia maximicarpa. The lobed perennial thallus, which can reach a height of 23 cm, is distinguished by its vegetative structure and by its unique pattern of nonprocarpic carposporophyte development. In transverse section, the blades consist of a narrow filamentous medullary layer sandwiched on either side by large ellipsoidal subcortical cells and a thin outer cortex. The monocarpogonial branch and auxiliary cell systems of the female plants are typical of many members of the Kallymeniaceae. However, after the carpogonialfusion cell forms, a distinctive developmental pattern begins. The connecting filaments radiate outward into the surrounding tissue, branch abundantly, and become septate. They then contact, in addition to auxiliary cells, many small moniliform accessory branches. These branches appear to act as initiation points for the gonimoblast filaments. The large diffuse carposporophytes produced are unknown in any other member of the Cryptonemiales. The vegetative and reproductive anatomy of Hommersandia is compared to other Kallymeniaceae, and similar patterns of postfertilization development are examined in the Rhodophyta.     

MORPHOLOGY AND SYSTEMATICS OF RHODOCALLIS ELEGANS, RHODOCALLIDEAE, TRIB. NOV. (CERAMIACEAE, RHODOPHYTA), FROM SOUTHEASTERN AUSTRALIA

Recent collections of Rhodocallis elegans Kützing from southeastern Australia have permitted detailed observations of vegetative and reproductive structures that reveal features not exhibited by any existing tribe of Ceramiaceae. As a consequence, we establish the new tribe Rhodocallideae based on the unispecific genus Rhodocallis. Defining characters include: 1) four periaxial cells cut off in an alternating (rhodomelaceous) sequence; 2) determinate branchlets of two types: a) persistent lateral branchlets produced from the first-formed periaxial cells, and b) deciduous transverse branchlets produced from the second and third periaxial cells, with cortical filaments issuing from all four periaxial cells; 3) first- and second-order determinate branchlets terminated by thick-walled spines; 4) indeterminate branches formed at the tips of directly converted determinate branchlets; 5) axial cells of indeterminate branches heavily corticated by a cylinder of descending rhizoidal filaments; 6) spermatangial parent cells borne directly on unmodified outer cortical cells; 7) carpogonial branches borne in series on second and third periaxial cells of modified indeterminate axes; 8) procarps lacking sterile-cell groups; 9) a single derivative of the zygote nucleus transferred from the carpogonium to the auxiliary cell directly through a tube rather than by means of a connecting cell; 10) gonimoblasts surrounded by a network of rhizoidal filaments through which the gonimolobes protrude, the carposporophyte subtended by an investment of determinate branchlets; and 11) tetrasporangia tetrahedrally divided, borne on surface cortical cells of special determinate branchlets and protruding outside the cuticular layer.     

THE RECLASSIFICATION OF LESSONIA LAMINARIOIDES (LAMINARIALES,PHAEOPHYCEAE): PSEUDOLESSONIA GEN. NOV.1

A new genus, Pseudolessonia, is proposed for the kelp Lessonia laminarioides Postels et Ruprecht (Laminariales, Phaeophyceae), which occurs on the northwest side of the Sea of Okhotsk, in the northwest Pacific Ocean. Pseudolessonia is monotypic and differs from Lessonia in its short primary stipes and its corrugated, unilaterally arranged blades with entire margins. This species is transferred on the basis of morphology and plastid gene sequence comparisons. We determined psaA and rbcL gene sequences from 17 taxa of Pseudolessonia, Lessonia, and putative relatives. Analyses of individual and combined data sets resulted in congruent trees showing a clear separation of Pseudolessonia laminarioides from Lessonia, but suggesting its sister relationships with the clade of Nereocystis, Macrocystis, Pelagophycus, and Postelsia in the North Pacific Ocean. On the other hand, Lessonia species from the South Pacific Ocean formed a strongly supported clade. The results indicate that the basal splitting of the blade, which has been considered a diagnostic character for the family Lessoniaceae, is a result of convergent evolution.