摘要

Specimens of Fallacia tenera were collected from the surface sediment at in a river estuary in Japan. Auxosporulation occurred in a rough culture. Morphological structures of vegetative cells and auxospores were observed in detail. The vegetative cells have one H-shaped chloroplast. The striae were interrupted by two depressed lateral sterna internally and partly covered by a finely porous conopeum on the external surface. The lateral sterna and porous conopea formed two more or less curved longitudinal canals connecting with the exterior via opening pores on both sides of a terminal fissure. This combination of characteristics is unique to the genus Fallacia. The cingulum was composed of three bands, such as an open valvocupula and two comparatively thin pleurae. The two pleurae could be distinguished by the shape of their ligulae. The second band had a triangular ligula, whereas the ligula of the third band is arc-shaped. The auxosporulation was type IA1a in Geitler's classification. Two paired gametangia formed two anisogametes in each of them. Two auxospores formed in the thecae of the gametangia after a trans physiological anisogamy. The perizonium of the auxospore consisted of a set of transverse bands and five longitudinal bands. The primary transverse band was about twice wider than the secondary ones. The circular incunabular scales were present on the two terminals of the auxospore and on the surface of the primary transverse band. The primary longitudinal band had an acute terminal and was flanked by secondary longitudinal bands. Each side had two secondary longitudinal bands. All longitudinal bands were immediately beneath the transverse bands. Morphological comparison between Fallacia and Pseudofallaica, and the taxonomic position of F. tenera is also discussed.

  • 出版日期2014-4-11