W. Smith 1855 Category: Asymmetrical biraphid
BASIONYM: Gomphonema elongatum W. Smith 1855
SYNONYM(S): Gomphonema acuminatum var. elongatum (W. Smith) Carruthers 1864
Contributor: Pat Kociolek - September 2011
Length Range: 40-105 µm
Width Range: 7-11 µm
Striae in 10 µm: 13-15
Valves acuminate-apiculate. The apex is protracted and blunt with a weakly expanded headpole. The central portion of the valve is tumid. The axial area is straight and wider at the apices than at the central valve. The central area is transversely widened, formed by two (one on each side) shortened central striae, and on one side is positioned a single isolated stigma. The punctate striae are radiate about the center, becoming parallel towards the ends, then becoming radiate at the headpole and footpole. The striae at the central valve are more widely spaced than the rest of the striae.
Basionym: Gomphonema elongatum
Author: W. Smith 1855
Length Range: µm
Striae in 10 µm:
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.