References:
Patrick, R. & Reimer, C. W (1966). The Diatoms of the United States I. Monographs of the Academy of Natural Sciences of Philadelphia. Pennsylvania. pp. 258; 286-287 (pl.16:25-26)
Synonyms:
Achnanthes exigua var. heterovalva Krasske 1923; Achnanthes exigua var. heterovalvata Krasske ex. Hustedt in Pasch. 1930
Description:
Patrick & Reimer (1966) describe the features for this variety as being identical to Achnanthes exigua; however, they note differences in striation on raphid valve (finer striae than in nominate form) as well as valve structure (there may or may not be constriction at the centre of valve sides); length is 10-15µm, breadth is 5-6µm; striae count is 30 in 10µm, becoming about 34 in 10µ on raphid valve, about 22 in 10µm on the araphid valve
Notes:
specimens recorded have been slightly larger in length and width than was described, with slightly higher striae counts
Projects:
Transect Project
