抄録
This study presents new information on the morphology of the brackish water species Achnanthes brevipes var. intermedia Kütz. based on the type slide and material. This taxon has been difficult to identify compared with A. brevipes C. Agardh var. brevipes because they resemble each other in the shape of the valve face. A. brevipes var. brevipes has valves that are usually more or less linear, slightly constricted at the centre and cuneate at the apices, and both valve faces are quite flat. On the other hand, var. inter-media has valves that are usually more or less elliptical with a rounder valve face. Furthermore, valve size of var. intermedia is smaller than var. brevipes. However, var. intermedia is not considered an independent species but should remain a variety of A. brevipes at this time because several structures that resemble each other are more than the differences between these two taxa. More observations are required about this taxon and the other species of A. brevipes complex to propose its specific rank.
