PROPOSAL OF THE GRACILARIALES ORD. NOV. (RHODOPHYTA) BASED ON AN ANALYSIS OF THE REPRODUCTIVE DEVELOPMENT OF GRACILARIA VERRUCOSA1

The mode of division of vegetative cells, formation of spermatangial parent cells, initiation of the carpogonial branch apparatus, and formation of tetrasporangial initials are homologous developmental processes that are documented for the first time in the type species of the economically important family Gracilariaceae, Gracilaria verrucosa (Hudson) Papenfuss from the British Isles. G. verrucosa is characterized by a supporting cell of intercalary origin that bears a 2-celled carpogonial branch flanked by two sterile branches, direct fusion of cells of sterile branches onto the carpogonium, formation of an extensive carpogonial fusion cell through the incorporation of additional gametophytic cells prior to gonimoblast initiation, gonimoblast initials produced from fusion cell lobes, schizogenous development of the cytocarp cavity, inner gonimoblast cells producing tubular nutritive cells that fuse with cells of the pericarp or floor of the cystocarp, absence of cytologically modified tissue in the floor of the cystocarp, and carposporangial initials produced in clusters or irregular chains. Spermatangial parent cells are generated in flaments from intercalary cortical cells that line an intercellular space forming a ‘pit’ or ‘conceptacle’. Tetrasporangial initials are transformed from terminal cells derived through division of an outer cortical cell. Tetrasporangia are cruciately divided. The Gracilariaceae is removed from Gigartinales and transferred to the new order Gracilariales. Their closest living relatives appear to be agarophytes belonging to the Gelidiales and Ahnfeltiales.     

INFRAGENERIC TAXONOMY OF AHNFELTIA (AHNFELTIALES,RHODOPHYTA)1

Ahnfeltia plicata (Hudson) Fries, the type species of Ahnfeltia Fries, is reported to be a widespread alga which is an important source of agar. However, after characterizing type material and representative populations of A. plicata, we found that several taxa usually considered to be synonyms of A. plicata instead represent separate species with differing geographic distributions. Ahnfeltia plicata sensu stricto is characterized by the development of external carposporophytes on female sori that are present only on mature axes. Pseudocarposporophytes bearing monosporangia and cortical monosporangial sori occur on both young and old axes. Characteristic vegetative features include long medullary cells and cortical growth rings. Ahnfeltia plicata s.s. is circumpolar in both hemispheres and is harvested for agar in the White Sea. Ahnfeltia setacea (Kútzing) Schmitz from the Falkland Islands, Gymnogongrus comosus Kützing from Chile and Gymnogongrus filiformis Kützing from southern Argentina appear to be synonymous with A. plicata. Ahnfeltia fastigiata (Postels et Ruprecht) Makienko, from the North Pacific, differs from A. plicata principally in the development of female sori and carposporophytes only near apices; medullary cells are shorter and cortical growth rings, cortical monosporangia and pseudocarposporophytes are not formed. It is dioecious and its life history involves the development from carpospores of a crustose Porphyrodiscus tetrasporophyte. We suggest that A. plicata var. tobuchiensis Kanno et Matsubara, the principal form of Ahnfeltia utilized for agar production in the North Pacific, represents an unattached ecad of A. fastigiata. Ahnfeltia elongata Montagne, known only from Chile and with carposporophytes restricted to main axes, is more closely related to A. plicata than to A. fastigiata. Thalli are large and regularly dichotomous, with long medullary cells, and do not form pseudocarposporophytes or monosporangia.     

CHARACTERIZATION OF MYHOGRAMME LNIDA, MYRIOGRAMMEAE TRIB. NOV (DELESSEIUACEAE, FWODOPHYTA)

The Myriogramme group of Kylin was found to contain two distinct clusters of genera that merit recognition at the tribal level. In this paper, we establish the tribe Myriogrammae based on a study of the type species of Myriogramme, M. livida, from the Southern Hemisphere. The Myriogrammae is characterized by 1) marginal and diffuse intercalary meristems; 2) nuclei arranged in a ring bordering the side walls of vegetative cells; 3) microscopic veins absent; 4) procarps scattered, formed opposite one another on both sides of the blade posterior to one or more vegetative pericentral cells (cover cells) and consisting of a carpogonial branch, a one-/to two-celled lateral sterile group and a one-celled basal sterile group; 5) auxiliary cell diploidized by a connecting cell cut off posteriolaterally from the fertilized carpogonium; 6) gonimoblast initial cut off distally from the auxiliary cell, generating one distal and one to two lateral gonimoblast filaments that branch in the plane of the expanding cystocarp cavity and later fuse to from an extensive, branched fusion cell; 7) spermatangial and tatrasporangial sori formed inside the margin on both sides of the blade by resumption of meristematic activity; and 8) tetrasporangia produced primarily from the central cells. The Myriogrammae currently includes Myriogramme Kylin , Gonimocolax Kylin , Haraldiophyllum A. Zinova , Hideophyllum A. Zinova, and a possible undescribed genus from Pacific North and South America. Genera are separated based primarily on features of gonimoblast and carposporangial development .     

THE LIFE HISTORIES OF RHODOCHORTON PURPUREUM AND R. TENUE IN CULTURE

The life histories of the red algae Rhodochorton purpureum and R. tenue were studied in unialgal culture. Telrasporophytes produced sporangia in short day regimes (8–12 hr) with 50–200 ft-c cool white light at 10 or 15 C. Mature gametophytes were not observed in the Washington and Alaska clones of R. purpureum. Tetraspores from R. tenue and the California clones of R. purpureum give rise to unisexual gametophytes that are reproductive when smaller than the tetrasporophytes. The tetrasporophytes develop directly from the gonimoblast cells. Because of similarities in morphology and life histories, it is proposed that R. tenue be placed in synonomy with R. purpureum.     

CHARACTERIZATION OF SCHIZOSERIS CONDENSATA,SCHIZOSERIDEAE TRIB. NOV. (DELESSERIACEAE,RHODOPHYTA)1

The Myriogramme group of Kylin contains two distinct clusters of genera that merit recognition at the tribal level. We previously established the tribe Myriogrammeae, and in this paper we erect the Schizoserideae based on a study of the type species of Schizoseris, S. laciniata (=S. condensata), from the southern hemisphere. The Schizoserideae is characterized by 1) marginal and diffuse intercalary meristems; 2) nuclei initially arranged in a plate in the median plane in meristematic and mature cells; 3) chloroplasts one to few, lobed or dissected; 4) microscopic veins absent; 5) procarps scattered, formed singly on either side of the blade with cover cells absent and consisting of a one- to two-celled lateral sterile group, a one- to two-celled basal sterile group, and a four-celled carpogonial branch in which the trichogyne passes beneath the lateral sterile group and emerges anterior to it; 6) auxiliary cell diploidized by a connecting cell cut off posteriolaterally from the fertilized carpogonium; 7) gonimoblast initial cut off laterally from one side of the auxiliary cell and giving rise to unilaterally branched gonimoblast filaments bearing carposporangia in branched chains; 8) gonimoblast fusion cell highly branched, candelabra-like, incorporating all but the basalmost cells of the carposporangial chains and radiating through the central cells in the floor of the cystocarp; 9) spermatangial and tetrasporangial sori formed from surface cells in both monostromatic and polystromatic portions on both sides of the blade; and 10) tetrasporangia formed primarily from cortical rather than from central cells. The Schizoserideae presently includes Schizoseris Kylin, Neuroglossum Kützing, Abroteia J. Agardh, and Polycoryne Skottsberg in Kylin and Skottsberg.     

Taxonomy of phyllophoroid algae: the implications of life history

The Phyllophoraceae Rabenhorst (Gigartinales) is a family that shows a great diversity of life history patterns. The three largest phyllophoroid genera, Ahnfeltia, Gymnogongrus and Phyllophora, all commercial sources of phycocolloids, show the greatest range of life history. Information from life history studies has been of significance to classification of the Phyllophoraceae at the family, generic and specific levels. In the tetrasporophyte of Ahnfeltia plicata, previously known as Porphyrodiscus simulans, tetrasporangia are zonate and borne terminally in small superficial sori in contrast to the chains of cruciate tetrasporangia characteristic of the Phyllophoraceae. A study of reproduction and life history in the type species, A. plicata, from the Atlantic concluded that the unique carposporophyte development, in conjunction with the most primitive pit-plug structure known in the Florideophycidae, justified the proposal of a new family Ahnfeltiaceae Maggs et Pueschel in the Ahnfeltiales Maggs et Pueschel. Most Pacific species of Ahnfeltia are instead phyllophoracean and closely related to Gymnogongrus. Gymnogongrus griffithsiae, the type species, forms tetrasporoblasts whereas the majority form internal cystocarps and have heteromorphic life histories. Proposals to divide the genus by life history type require further detailed morphological and ontogenetic studies of G. griffithsiae. Phyllophora species exhibit at least three different types of life history, tetrasporoblastic, isomorphic and heteromorphic, and this genus could likewise be split along these lines. At the specific level, intraspecific life history variability appears to be related to morphological variation in some species of Gymnogongrus.     

Grammephora peyssonnelioides gen. et sp. nov. (Rhodophyta, Rhodymeniaceae) from the Solomon Islands, South Pacific

A new genus and species of red alga in the Rhodymeniaceae, Grammephora peyssonnelioides, is described from both shallow and deepwater habitats in the Solomon Islands, South Pacific. The new genus and species is characterized by prostrate overlapping lobes with a strongly cartilaginous flexible texture, distinct surface linear markings perpendicular to the growing margins, and a compact three to four celled medulla of relatively small refractive cells. Tetrasporangia are elongate and decussately divided, and occur in large scattered dorsal surface sori. Cystocarps are prominent and conical, on the dorsal surface of the blade, with a network of nutritive filaments and basal nutritive tissue around the suspended, centrally located carposporophyte, with all gonimoblast initials becoming carposporangia. The columnar fusion cell is uniquely crowned by a ring of discoid cells of nonalgal origin.     

The occurrence of a Porphyrodiscus simulans Batt. phase in the life history of Ahnfeltia plicata (Huds.) Fries

Plants of Ahnfeltia plicata (Huds.) Fries collected from various localities in the North Atlantic were found to have arisen from basal tetrasporangial crusts identifiable as Porphyrodiscus simulans Batt. Tetraspores from the Porphyrodiscus crusts were cultured for the first time and were found to give rise to discs morphologically similar to those produced by the monospores of Ahnfeltia plicata.     

A phylogenetic re‐appraisal of the family Liagoraceae sensu lato (Nemaliales,Rhodophyta) based on sequence analyses of two plastid genes and postfertilization development

The marine red algal family Liagoraceae sensu lato is shown to be polyphyletic based on analyses of a combined rbcL and psaA data set and the pattern of carposporophyte development. Fifteen of eighteen genera analyzed formed a monophyletic lineage that included the genus Liagora. Nemalion did not cluster with Liagoraceae sensu stricto, and Nemaliaceae is reinstated, characterized morphologically by the formation of the primary gonimolobes by longitudinal divisions of the gonimoblast initial. Yamadaella and Liagoropsis, previously placed in the Dermonemataceae, are shown to be independent lineages and are recognized as two new families Yamadaellaceae and Liagoropsidaceae. Yamadaellaceae is characterized by two gonimoblast initials cut off bilaterally from the fertilized carpogonium and diffusely spreading gonimoblast filaments. Liagoropsidaceae is characterized by at least three gonimoblast initials cut off by longitudinal septa from the fertilized carpogonium. In contrast, Liagoraceae sensu stricto is characterized by a single gonimoblast initial cut off transversely or diagonally from the fertilized carpogonium. Reproductive features, such as diffuse gonimoblasts and unfused carpogonial branches following postfertilization, appear to have evolved on more than one occasion in the Nemaliales and are therefore not taxonomically diagnostic at the family level, although they may be useful in recognizing genera.     

REPRODUCTION AND LIFE HISTORY OF THE RED ALGA GALAXAURA OBLONGATA (NEMALIALES,GALAXAURACEAE)1

Culture and morphological studies showed that Galaxaura oblongata (Ellis et Solander) Lamouroux has a triphasic life history with conspicuous gametophytes and small filamentous tetrasporophytes. Development of male and female reproductive structures is very similar and both begin with the enlargement of a terminal cell of a filament branch occupying a normal vegetative position within the apical pit of a thallus branch. In male thalli this modified branch forms a conceptacle in which spermatangia are produced. In female thalli, this modified branch forms a three-celled carpogonial branch consisting of a carpogonium, hypogynous cell and basal cell. Filament branches from the basal cell form a pericarp and the gonimoblast develops directly from the carpogonium. Carposporangia are produced in conceptacles which resemble the male conceptacles. About the time the first carposporangia are produced, the carpogonium, hypogynous cell and basal cell form a large fusion cell. Released carpospores germinate in a unipolar or bipolar manner and form small filamentous thalli. Under short day conditions, cruciate tetrasporangia are produced in small clusters. Tetraspores germinate similarly to carpospores and also form small filamentous thalli. Under low nutrient conditions, small cylindrical thalli develop on the filaments and these appear similar to gametophytes collected in nature.     

ONTOGENY OF SEXUAL CONCEPTACLES IN A SPECIES OF BOSSIELLA (CORALLINACEAE)1

The first evidence of conceptacle formation in male and female plants of Bossiella californica ssp. Schmittii is the secretion of a cap below the epithallium. Subsequent development involves the disintegration of the upper enucleate parts of cortical cells below the center of the cap concomitant with the growth of tissue surrounding these cells. Protoplasts in the lower parts of these cortical cells recover and become initials of reproductive cells. Differentiation of each initial in female plants results in a supporting cells bearing 1 or 2, 2-celled carpogonial filaments, and in male plants results in a basal cell bearing 2 or 3 spermatangial mother cells which bud off spermatangia. Following fertilization, supporting cells fuse and form a broad, thin fusion cell from the upper surface of which gonimoblast (carposporangial) filaments arise.     

Molecular phylogeny and developmental studies of Apoglossum and Paraglossum (Delesseriaceae,Rhodophyta) with a description of Apoglosseae trib. nov.

Our morphological and molecular studies indicate that species from the southern hemisphere previously placed in Delesseria belong in Paraglossum and that Paraglossum and Apoglossum comprise a separate tribe, the Apoglosseae, S.-W. Lin, Fredericq & Hommersand, trib. nov., within the family Delesseriaceae. From a vegetative perspective the Apoglosseae is readily recognized because some or all fourth-order cell rows are formed on the inner sides of third-order cell rows. All fourth-order cell rows grow adaxially in Apoglossum, whereas both adaxial and abaxial cell rows are present in Paraglossum. Periaxial cells do not divide in Apoglossum, whereas they divide transversely in Paraglossum in the same way as in Delesseria. Major branches are formed mainly from the margins of midribs in the Apoglosseae. The procarp consists of a straight carpogonial branch and two sterile cells, with the second formed on the same side as the first. The carpogonium cuts off two connecting cells in tandem from its apical end, the terminal cell being nonfunctional and the subterminal cell typically fusing with the auxiliary cell. Gonimoblast filaments radiate in all directions from the gonimoblast initials and produce carposporangia terminally in branched chains, with pit connections between the inner gonimoblast cells broadening and enlarging. The auxiliary cell, supporting cell, and sterile cells unite into a fusion cell, which remains small in Apoglossum but incorporates the branched inner gonimoblast filaments and cells in the floor of the cystocarp in Paraglossum. Elongated inner cortical cells seen in mature cystocarps in the Delesserieae are absent in the Apoglosseae. Phylogenetic studies based on rbcL (RuBisCO large subunit gene) sequence analyses strongly support the recognition of the Apoglosseae within the subfamily Delesserioideae of the Delesseriaceae, in agreement with our previous observations based primarily on analyses of large subunit ribosomal DNA (LSU).     

MORPHOLOGY OF PLACENTOPHORA (SOLIERIACEAE,GIGARTINALES: RHODOPHYTA), A NEW GENUS BASED ON SARCODIOTHECA COLENSOI FROM NEW ZEALAND1

The only member of the red algal family Solieriaceae known from New Zealand is the endemic Sarcodiotheca colensoi (Hook. & Harv.) Kylin. This study shows that it differs in several respects from the type S. furcata (Setch. & Gard.) Kylin; thus a new genus Placentophora is created for the New Zealand alga. Although P. colensoi nov. comb. is retained in the Solieriaceae on the basis of vegetative, spermatangial, tetrasporangial, carpogonial-branch and early gonimoblast features, it differs from typical members of that family in its pattern of later carposporophyte development. After a single gonimoblast initial is cut off from the auxiliary cell towards the center of the thallus, further gonimoblasts develop from the initial as ramifying, radiating filaments. These filaments enter an extensive “nutritive-cell” region surrounding the auxiliary cell, form, numerous connections to the “nutritive” cells, and incorporate most of them into a central placenta of interconnected, and variously-fused vegetative and gonimoblast cells. Carpo-sporangia then form in short chains around the periphery of the placenta. The cystocarp lacks both a central fusion cell and a sterile-celled investment, or “Faserhülle.” The distinctive carposporophyte of Placentophora is compared to patterns of gonimoblast development, known in other members of the Solieriaceae.     

SYSTEMATIC REVISION OF THE GENERA LIAGORA AND IZZIELLA (LIAGORACEAE,RHODOPHYTA) FROM TAIWAN BASED ON MOLECULAR ANALYSES AND CARPOSPOROPHYTE DEVELOPMENT,WITH THE DESCRIPTION OF TWO NEW SPECIES1

Some Liagora and Izziella distributed in Taiwan display a wide range of morphological variation and can be difficult to distinguish. To clarify species concepts, we applied DNA sequence analyses and examined carposporophyte development in detail. These studies revealed two new species, which are described herein as Izziella hommersandii sp. nov. and Izziella kuroshioensis sp. nov. I. kuroshioensis superficially resembles Izziella formosana and Izziella orientalis in that its involucral filaments subtend rather than surround the lower portion of the gonimoblast mass (= Izziella type) and a fusion cell is formed from cells of the carpogonial branch, but it can be separated by differences in the cell numbers and branching pattern of the involucral filaments, as well as thallus morphology. In contrast to other species that also bear short lateral branchlets, I. hommersandii is unique in possessing a mixture of short and long involucral filaments, a phenomenon not reported before. The length of the involucral filaments is species specific among species of Izziella and contrasts to the behavior of the involucral filaments after fertilization in species such as “Liagora”setchellii [= Titanophycus setchellii comb. nov.], in which the filaments completely envelop the gonimoblast. In addition, the cells of the carpogonial branch in Titanophycus do not fuse after fertilization to form a fusion cell. Thus, a combination of characters with respect to the behavior of the carpogonial branch and the involucral filaments after fertilization is very useful for delineating species boundaries in Izziella and for separating Titanophycus from Izziella and Liagora.     

Studies of the Liagoraceae (rhodophyta) of Western Australia: Gloiotrichus fractalis gen. et sp. nov. and Ganonema helminthaxis sp. nov.

Two new taxa of Liagoraceae (Nemaliales) are described from Western Australia. Gloiotrichus fractalis gen. et sp. nov. has been collected from 3–20 m depths at the Houtman Abrolhos, Western Australia. Plants are calcified, extremely lubricous, and grow to 17 cm in length. Carpogonial branches are straight, 6 or 7 cells in length, arise from the basal or lower cells of cortical fascicles, and are occasionally compound. Branched sterile filaments of narrow elongate cells arise on the lower cells of the carpogonial branch prior to gonimoblast initiation, at first on the basal cells, then on progressively more distal cells. Following presumed fertilisation the carpogonium divides transversely, with both cells giving rise to gonimoblast filaments. The distal cells of the carpogonial branch then begin to fuse, with fusion progressing proximally until most of the cells of the carpogonial branch are included. As fusion extends, the filaments on the carpogonial branch are reduced to the basal 2 or 3 cells. The gonimoblast is compact and bears terminal carposporangia. Spermatangial clusters arise on subterminal cells of the cortex, eventually displacing the terminal cells. The sequence of pre- and post-fertilisation events occurring in the new genus separates it from all others included in the Liagoraceae, although it appears to have close affinities with the uncalcified genus Nemalion. Ganonema helminthaxis sp. nov. was collected from 12 m depths at Rottnest Island, Western Australia. Plants are uncalcified and mucilaginous, the axes consisting of a few (< 10) primary medullary filaments, each cell of which gives rise to a cortical fascicle at alternate forks of the pseudodichotomies borne on successive medullary cells. Subsidiary (adventitious) filaments and rhizoids comprise the bulk of the thallus. Carpogonial branches are straight, (3-)4(-6) cells in length, arise on the basal 1–4 cells of the cortical fascicles, and are frequently compound. Carposporophytes develop from the upper of two daughter cells formed by a transverse division of the fertilised carpogonium. Ascending and descending sterile filaments girdle the carpogonial branch cells and arise mostly on the supporting cell prior to fertilisation. Ganonema helminthaxis is the first completely non-calcified member of the genus, and its reproductive and vegetative morphology supports the recognition of Ganonema as a genus independent from Liagora. Liagora codii Womersley is a southern Australian species displaying features of Ganonema, to which it is transferred.     

THE GENUS PIKEA (DUMONTIACEAE,RHODOPHYTA) IN ENGLAND AND THE NORTH PACIFIC: COMPARATIVE MORPHOLOGICAL,LIFE HISTORY,AND MOLECULAR STUDIES1

A Pikea species attributed to Pikea californica Harvey has been established in England since at least 1967. Previously, this species was believed to occur only in Japan and Pacific North America. Comparative morphological studies on field-collected material and cultured isolates from England, California, and Japan and analysis of organellar DNA restriction fragment length polymorphisms, detected using labeled organellar DNA as a non-radioactive probe, showed that English Pikea is conspecific with P. californica from California. Both populations consist of dioecious gametophytes with heteromorphic life histories involving crustose tetrasporophytes; 96% of organellar DNA bands were shared between interoceanic samples. A second dioecious species of Pikea, P. pinnata Setchell in Collins, Holden et Setchell, grows sympatrically with P. californica near San Francisco but can be distinguished by softer texture, more regular branching pattern, and elongate cystocarpic axes. Pikea pinnata and P. californica samples shared 49–50% of organellar DNA bands, consistent with their being distinct species. Herbarium specimens of P. robusta Abbott resemble P. pinnata in some morphological features but axes are much wider; P. robusta may represent a further, strictly sub-tidal species but fertile material is unknown. Pikea thalli from Japan, previously attributed to P. californica and described here as Pikea yoshizakii sp. nov., are monoecious and show a strikingly different type of life history. After fertilization, gonimoblast filaments grow outward through the cortex and form tetrasporangial nemathecia; released tetraspores develop directly into erect thalli. Tetrasporoblastic life histories are characteristic of certain members of the Phyllophoraceae but were previously unknown in the Dumontiaceae. Japanese P. yoshizakii shared 55 and 56% of organellar DNA bands with P. californica and P. pinnata, respectively; phylogenetic analysis indicated equally distant relationships to both species. Pikea yoshizakii or a closely similar species with the same life history occurs in southern California and Mexico.     

The morphology and ecology of Nemastoma and Predaea species (Nemastomataceae,Rhodophyta) from Ghana

Two members of the family Nemastomataceae (Gigartinales, Rhodophyta) are described from subtidal habitats in Ghana. Nemastoma confusum sp. nov. is a plant of irregularly lobed, thick gelatinous blades with subacute marginal projections and surface proliferations. It is composed of a lax medulla and submoniliform cortical filaments with prominent intercalary gland cells. Carposporophytes are one to three spherical lobes of carposporangia borne on gonimoblast initials arising directly from auxiliary cells contacted by connecting filaments. A rudimentary involucre is formed around the gonimoblast by elongating vegetative cortical cells borne on the auxiliary cell. The genus Predaea is recorded for the first time from Africa, and P. feldmannii Boerg. is described in morphological detail together with some observations on its ecology in Ghana. Distinctive features of connecting filament formation, nutritive cell production and gonimoblast initiation and development are illustrated and compared to other species of the genus. A second species, P. masonii (Setch. & Gardn.) De Toni fil., is represented by a single specimen in the collections and appears to be distinct from P. feldmannii on cortical and gland cell features.     

WAERNIA MIRABILIS GEN. NOV., SP. NOV. (DUMONTIACEAE,GIGARTINALES): A NEW NONCORALLINE CRUSTOSE RED ALGA FROM THE NORTHWESTERN ATLANTIC OCEAN AND ITS RELATIONSHIP TO GAINIA AND BLINKSIA1

Waernia mirabilis Wilce, Maggs et Sears, gen. et sp. nov., is described for an encrusting red alga endemic to the northeastern North Atlantic Ocean. Its perennial thalli form major understory populations that may outcompete Corallinaceae and Hildenbrandiaceae in some habitats. Crustose red algae with isomorphic gametophytes and tetrasporophytes other than Corallinaceae are poorly known; Waernia differs vegetatively and reproductively from any other such algae. Gametangia are similar to those of the monotypic uncalcified crustose genera Blinksia and Gainia endemic to the Antarctic and central coastal California, respectively. Comparison of Waernia with type material of Blinksia californica Abbott & Hollenberg and Gainia mollis Moe shows that it differs from Blinksia in lacking cohesive crusts in which adjacent cells cohere by direct fusions and by its strongly recurved, rather than straight, carpogonial branches. Gainia and Waernia both have strongly recurved carpogonial branches and laxly constructed crusts that lack secondary pit connections. Gainia differs from Waernia in its considerably larger and thicker crusts, non‐nemathecial tetrasporangia, shorter carpogonial branches, and its consistently single gonimoblast initial. We continue to recognize the family Blinksiaceae as a probable member of the Gigartinales with uncertain affinities. Waernia is assigned to the Dumontiaceae (Gigartinales), as its first described isomorphic crustose member. It is also the only genus and one of few algal species endemic to northeastern North America. Waernia either arrived at its present distribution via migration from a Tertiary polar ocean or evolved from an unknown ancestor in a newly formed boreal northwest Atlantic Ocean during post‐Oligocene millennia.     

ULTRASTRUCTURE OF AUXILIARY AND GONIMOBLAST CELLS DURING CARPOSPOROPHYTE DEVELOPMENT IN FAUCHEOCOLAX ATTENUATA (RHODOPHYTA)1

The ultra structure of post-fertilization development in Faucheocolax attenuata Setch. is described. Following fertilization and transfer of the diploid nucleus to the auxiliary cell, four gonimoblast initials usually are produced of the multinucleate auxiliary cell. Gonimoblast initials originally are uninucleate but undergo karyokinesis to form multinudeate gonimoblast cells. Terminal or generative gonimoblast cells cleave successively to form lobes of incipient carpospores, with each group of spores differentiating synchronously. Portions of the initial generative gonimoblast cells, however, remain to resume karyokinesis and repeat the process of cleavage into carpospores. Axial gonimoblast cells are transformed into secretory cells, which produce mucilage. Generative gonimoblast cells and auxiliary cells are similar in cellular structure. Both contain typical red algal proplastids, some dictyosomes, cytoplasmic concentric membranes, and numerous small vesicles. In addition, dark staining spherical masses, occurring in the cytoplasm of all cell types, may represent dehydrated haploid chromatin. Large septal plugs interconnect gonimoblast cells and the auxiliary cell. These plugs are small when first formed but increase dramatically in size during carposporophyte development.     

The life history of Ahnfeltiopsis paradoxa (Gigartinales, Rhodophyta) in laboratory culture

The life history of the red alga Ahnfeltiopsis paradoxa (Suringar) Masuda (Phyllophoraceae, Gigartinales) from Japan was completed in laboratory culture. Carpospores isolated from field-collected plants germinated to form circular crusts that were composed of a monostromatic hypothallium consisting of radiating filaments, a polystromatic perithallium consisting of tightly coalescent erect filaments, and hypobasal tissue derived from the hypothallium. The crusts were induced to sporulate by transferring them from short-day to long-day regimes at 15° and 2°C. Each crust produced several nemathecia along 1-4 concentric rings. Intercalary, cruciately or decussately divided tetrasporangia were formed in 4-6 (1-2 at the margin of the nemathecium) successive cells of a single filament of the nemathecia. Tetraspore germlings gave rise to basal discs from which upright axes developed. The upright axes first grew without branches or were sparsely branched and later bore many marginal reproductive proliferations. Procarps and spermatangia were formed in the proliferations on different individuals. Carposporophytes developed on female plants that were co-cultured with male plants. Gonimoblast filaments were formed from an auxiliary cell that fused with a carpogonium. Carposporangia developed from gonimoblast filaments and medullary cells contacted by the gonimoblast filaments. Carpospores were discharged through carpostomes formed in the thickened cortex. Tetraspores were cultured from field-collected crusts of a morphology similar to that of cultured tetrasporophytes. They gave rise to upright gametophytic axes similar in morphology to this species as seen in the field.