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A taxonomic revision of Lobophora based on molecular phylogenetic analyses of rbcL and cox3 gene sequences as well as anatomical observations was carried out, mostly based on specimens collected from eastern Asia and southeastern Australia. In the molecular phylogenetic analyses, nine major clades supported by high bootstrap values were recognized. In combination with evaluation of morphological characters, four clades were concluded to be new species. The Australian species L. australis sp. nov. possessed erect thalli with sporangial son scattered on the ventral surface and had a closer phylogenetic relationship with another Australian species, L. nigrescens, but it was distinguished from the latter in having fewer layers of cortical cells and smaller sporangia. The Asian species L. crassa sp. nov., L. pachyventera sp. nov. and L. asiatica sp. nov. possessed decumbent thalli with sporangia scattered on the dorsal surface. Among the three prostrate species, L. crassa had a considerably thicker thallus with four to five cortical layers, L. asiatica had a thinner thallus with two cortical layers, and L. pachyventera differed from another two species by its three-layered ventral cortex and well-developed anchoring rhizoids. [ABSTRACT FROM AUTHOR]

Chara braunii is a charalean species that grows in a range of aquatic habitats from shallow water in paddy fields to the bottom of deep lakes. More than 30 infraspecific taxa have been proposed within this species because of its morphological variability. In order to reexamine the infraspecific taxa and habitat preference of C. braunii, we carried out molecular phylogenetic analyses and quantitative measurements of morphological characters used for infraspecific taxa, based on samples collected from various habitats and localities in Japan. Sequence data from the gene encoding the large subunit of Rubisco (rbcL) and the intergenic spacer regions between the beta subunit of the ATP synthase and rbcL genes demonstrated two robust clades (groups A and B). Samples of group A were collected mainly from shallow aquatic environments (< 15 cm in depth) such as paddy fields, while those of group B were mainly composed of samples found in deep aquatic environments (> 1 m in depth) such as lakes or ponds. Groups A and B therefore seem to represent closely related entities that have recently differentiated and might adapt to two different aquatic environments. However, the morphological measurements suggested these groups can be delineated by neither of the traditional diagnoses that were different between infraspecific taxa of Japanese plants of C. braunii. [ABSTRACT FROM AUTHOR]

The present study clarifies the fine structure of the vegetative frustules, initial valves and perizonium of Achnanthes crenulata Grunow. The valves of the vegetative cell are distinctly linear-lanceolate with an undulate margin. The valve face is quite flat and in girdle view is smoothly curved as in species of Gephyria (Bacillariophyceae). However, the valve face of the initial cells is slightly rounded and does not have an undulate margin. Furthermore, the rapheless sternum is centrally positioned along the apical axis of the araphid initial valve. As this taxon develops from auxospore to initial valve, it forms only longitudinal perizonial bands; no transverse bands arise. The perizonium consists of three silicified bands: one large, central longitudinal plate and two bands that underlie this plate; these two bands are either open or closed. This taxon has several conspicuous structures compared to other marine species of Achnanthes, but the structure of the perizonium supports the position of A. crenulata within Achnanthes sensu stricto. [ABSTRACT FROM AUTHOR]

SUMMARYThe morphology and fine valve structure of the marine epiphytic diatom Cocconeis heteroidea Hantzsch have been investigated. The entire frustule, including the internal and external structure of the raphid valve (RV) and araphid valve (AV), and the complete cingulum, are described using light microscopy and scanning and transmission electron microscopy, using a bleaching method. The strongly sigmoid raphe terminates in elongate hooked helictoglossae internally. The hymenes, with perforations arranged in a centric array, are located near the internal openings of the areolae in the RV. The striae in the AV consist of alveoli occluded by hymenes, that have perforations arranged in a parallel array and are located near the outer surface. The complete cingulum of AV consists of three open bands without fimbriae: a valvocopula, a copula with a ligula and a pleura with a small ligula. The RV has only a valvocopula which is open type and not fimbriate. [ABSTRACT FROM AUTHOR]

SUMMARYA new species of Cocconeis has been found growing on the green seaweed Caulerpa racemosa (Forsskål) J. Agardh var. laete-virens (Montagne) Weber van Bosse from Shikine Island in the Izu Islands on the Pacific coast of Japan; we propose the name Cocconeis shikinensis Hid. Suzuki and describe the species by light microscopy (LM) and electron microscopy (EM). This taxon was also collected from the plastic plates used for rearing in seed production systems of the abalone Nordotis discus hannai Ino and the horned turban Turbo cornutus Solander in the Toyama Prefectural Fisheries Research Institute facing the Sea of Japan. The main morphological features of C. shikinensis are as follows. The valves are elliptic. The valve face of the raphid valve (RV) is slightly concave and that of the araphid valve (AV) is complementary to the RV and convex. The single plastid is flat, C-shaped and elaborately lobed. The raphe on the RV is straight. The each terminal area expands to both sides along the valve margin, forming an arrowhead-shaped, thickened hyaline area. The striae consist of small, round areolae and are radiate and uniseriate. On the AV, the striae consist of several alveoli. Each alveolus opens internally by means of a circular foramen. The valvocopula of each valve is fimbriate and open. The cingulum attached to the AV consists of three girdle bands; a valvocopula and two bands (copula and pleura), which are open and have ligulae. The relationship between C. shikinensis and similar members of the genus Cocconeis is discussed. [ABSTRACT FROM AUTHOR]

Reports on the use of morphological comparisons, hybridization experiments and molecular phylogenetic analyses using the RUBISCO spacer region on 12 populations of red algae Caloglossa leprieurii and C. apomeiotica in order to identify their relationships. Indication that the asexual species was derived from sexual plants of the multiple cell row type; Correlation of reproductive compatibility with genetic distance rather than geographical distance.