Kützing 1844 Category: Symmetrical biraphid
TYPE SPECIES: Diadesmis confervacea Kützing
Diadesmis is biraphid, although the raphe often becomes secondarily filled with silica. Frustules of Diadesmis are small, usually less than 30 µm in length. The striae are composed of areolae elongated in the transapical direction, a characteristic that may be difficult to discern in the LM. Frustules form band-like colonies, which may be linked by marginal spines. The raphe systems of many frustules are secondarily filled with silica, and a raphe may not be evident in valve view. In girdle view, however, a central nodule and helictoglossa may be seen - evidence of the presence of a raphe.
Diadesmis is considered an aerophilic taxon. It grows on mosses and on damp rocks, often in low conductivity, slightly acid waters. With the description of the new genus Humidophila, Diadesmis now includes D. confervacea and varieties.
Cite This Page:
Spaulding, S., and Edlund, M. (2008). Diadesmis. In Diatoms of the United States. Retrieved April 26, 2015, from http://westerndiatoms.colorado.edu/taxa/genus/Diadesmis
In 2014, Lowe et al. published a new genus, Humidophila to include a large number of species that had been included in the genus Diadesmis. The page for Diadesmis has been edited to reflect the new, narrower concept of the type of D. confervacea. - S. Spaulding