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 .     

Phylogenetic analyses of anatomical and nuclear SSU rDNA sequence data indicate that the Dasyaceae and Delesseriaceae (Ceramiales,Rhodophyta) are polyphyletic

The aim of the current investigation was to test the general convention that the Dasyaceae, Delesseriaceae and Rhodomelaceae are all monophyletic families of the red algal order Ceramiales. Phylogenetic relationships among 45 ceramialean taxa were determined, including eight ceramiacean, 18 dasyacean, nine delesseriacean and eight rhodomelacean species, plus two of uncertain ceramialean affinities, based on 34 anatomical characters and nuclear small subunit (SSU) rDNA sequences. Results from our ‘total-evidence’ approach were consistent with the notion that the Dasyaceae, Delesseriaceae and Rhodomelaceae have evolved from a common ancestor within a paraphyletic Ceramiaceae. Our data indicate, however, that the Rhodomelaceae alone is monophyletic at the family level, with both the Dasyaceae and Delesseriaceae polyphyletic. In particular we resolved two independent and well-supported lineages for the included Dasyaceae, viz., a Dasya group and a Heterosiphonia group, which were as distinct from one another as they were from the Rhodomelaceae and the various lineages of Delesseriaceae. The molecular data alone were equivocal on the issue of monophyly of the Dasyaceae. We therefore advocate conservative taxonomic revisions as an interim step towards eventual resolution of familial-level taxonomy in the Ceramiales. Based on our results, the Heterosiphonioideae H.-G. Choi, Kraft, I.K. Lee et G.W. Saunders subfam. nov. is proposed for Heterosiphonia and five closely related genera, and the Dasyoideae Schmitz et Falkenberg is emended for the remaining taxa. Although the Dasyoideae is a natural group, it is in need of a thorough systematic reinvestigation at the generic level. Our analyses indicate that the genus Dasya is polyphyletic or paraphyletic in excluding Dasysiphonia, Eupogodon and Rhodoptilum and that Heterosiphonia japonica also has affinities to this group, taxonomic issues that will be addressed in detail elsewhere.     

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.     

Editorial note

Phylogenetic analyses of the Dasyaceae based on sequence analysis of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) and 42 morphological characters are presented. Comparative sequence analysis confirms the general view of the Ceramiaceae as a primitive, paraphyletic group giving rise to the Rhodomelaceae, Delesseriaceae and Dasyaceae within the monophyletic Ceramiales. On the basis of both data sets, the Heterosiphonia-like genera (Heterosiphonia, Colacodasya and Dasyella) are the most primitive members of the Dasyaceae, whereas the Dasya-like genera (Dasya, Pogonophorella, Eupogodon and Rhodoptilum) and Thuretia and Dictyurus are of more recent origin. On the basis of morphological data only, Thuretia and Dictyurus form a sister group to Heterosiphonia, and Eupogodon is monophyletic whereas Dasya and Heterosiphonia are not. Primary radial symmetry has arisen once in the Dasya clade but is secondarily obscured in some species by heavy, asymmetrical cortication that gives the appearance of bilateral symmetry. This is illustrated by species of Eupogodon and Rhodoptilum.     

Caloglossa intermedia, sp. nov. (Rhodophyta) from the western atlantic coast: molecular and morphological analyses with special reference to C. leprieurii and C. monosticha

Caloglossa intermedia , sp. nov. is described from estuaries and salt marshes of Atlantic North America. This species is related to C. leprieurii (Montagne) G. Martens based on the position of rhizoids, whereas it is more similar to C. monosticha Kamiya in the number of cell rows at the nodes. Rhizoidal development of this alga also shows an intermediate characteristic between C. leprieurii and C. monosticha. Crosses were successful between the strains of C. intermedia from Georgia and South Carolina, but neither strain was interfertile with morphologically related species. C. intermedia from Georgia, New Jersey, and South Carolina had identical DNA sequences in the Rubisco spacer and flanking regions of rbc L and rbc S. This alga was more closely related to C. leprieurii in a molecular phylogenetic analysis. The evolution of each morphological character is discussed.     

The morphology and taxonomy of Womersleya monanthos, an endemic species and genus of Delesseriaceae (Ceramiales, Rhodophyta) from southeastern Australia

Womersleya monanthos (J. Agardh) Papenfuss is typically an epiphyte of larger brown and red algae that are common in drift along the southeastern coasts of Australia. A hitherto little-known member of the Phycodrys group of the Nitophylloideae, its reproductive features have been studied in detail and its taxonomic position clarified. Blades are polystromatic throughout and lack veins or nerves, with blades originating from apical cells of primary and second-order cell rows. Intercalary cell divisions take place in primary cell rows and all other branch orders, with third-order laterals arising both abaxially and adaxially on cells of second-order rows. Fertile central cells bear procarps on pericentral cells on both sides of the blade, the procarps consisting of two 4-celled carpogonial branches and a single central group of sterile cells that enlarge and persist at the distal end of a bicampanulate fusion cell at maturity. Spermatangia and tetrasporangia form in circular subapical sori on both sides of the blade or in marginal lobes or proliferations. After comparing it to other members of the Phycodrys group, we conclude that Womersleya is a monotypic genus well distinguished from other genera and with probable closest affinities to the Northern Hemisphere Polyneura, Erythroglossum and Sorella, as well as the Australian endemic, Crassilingua.     

Erythroglossum latum sp. nov. (Delesseriaceae, Rhodophyta) from the east coast of Honshu, Japan

A new species, Erythroglossum latum, is described based on specimens from Fukushima Prefecture along the east coast of Honshu, Japan. This species differs from Erythroglossum pinnatum Okamura in having a broader main blade, a clear midrib and lateral branches that are smaller in size and not clearly constricted at the base.