Algae. 2001; 16(4): 387-409.

Morphology and Reproduction of Heterosiphonia pulchra and H. japonica (Ceramiales, Rhodophyta)

Han-Gu Choi

School of Biological Sciences, Seoul National University

Two species of Heterosiphonia (Dasyaceae, Ceramiales), H. pulchra (Okamura) Falkenberg and H. japonica Yendo were reported in Korea. The aim of this study was to re-evaluate taxonomic criteria for these two species, based on anatomical features of vegetative and reproductive structures. Samples were collected in places from the lower intertidal to the subtidal zone on coasts of Korea. Heterosiphonia pulchra occurred throughout the year with tetrasporangia and cystocarps, while H. japonica scarcely showed the female and male reproductive structures in the field. Two species share stable and typical characteristics of the family Dasyaceae such as sympodial growth and formation of tetrasporangial stichidia with tetraspores being formed acropetally and whorledly. Heterosiphonia pulchra has some diagnostic features: mono- and polysiphonous pseudolateral branches emerging at every two to four segments, the pericentral cells forming in rhodomelacean sequence, polysiphonous pedicellate stichidia and procarps formed on the determinate branches, which are commonly found in other Heterosiphonia spp. Heterosiphonia japonica, however, shows other characteristics: monopodial pseudolaterals produced at every segment, monosiphonous pedicellate stichidia and procarps formed on the indeterminate branches, which are features seen in Dasysiphonia spp. The latter species has a unique feature with the pericental cells formed in laterally transverse sequence within the Dasyaceae. The taxonomy of the two species of Heterosiphonia and the related species within the genus is discussed.

Keywords : Ceramiales, Dasyaceae, Heterosiphonia, H. japonica, H. pulchra, morphology, reproduction, Rhodophyta, taxonomy