Algae. 2001; 16(1): 35-43.

The Circumscription of the Genus Halothrix Reinke (Chordariales, Phaeophyceae)

Yongpil Lee

Department of Biology, Cheju National University

The entity of the genus Halothrix was reappraised based on the descriptions and figures of authentic references. Halothrix is characterized by a tuft of simple erect filaments and forming dense girdles of producing plurilocular sporangial sori around the erect filaments, absence of parenchymatous medullary core, absence of paraphysis (short assimilator), and absence of phaeophycean hairs. Consequently, those species with paraphyses and medullary cores, H. ambigua Yamada, H. tortuosa Takamatsu, and H. ephemeralis Skinner, should be excluded from the genus Halothrix. Halothrix rectiuscula sp. nov. is characteristic in erect filaments tapering much slowly toward apex, continuous covering of plurilocular sporangial sori on erect filament, and simultaneous formation of plurilocular sporangia on the cells of erect filament.

Keywords : Chordariales, Halothrix, H. lumbricalis, H. rectiuscula sp. nov., taxonomy