Lange-Bertalot and Metzeltin 1996 Category: Symmetrical biraphid
TYPE SPECIES: Geissleria moseri Metzeltin, Witkowski and Lange-Bertalot in Lange-Bertalot and Metzeltin
Smallest to largest - 7 taxa sorted by maximum length
Geissleria valves are elliptic to linear-elliptic, becoming obtuse, broadly rounded or rostrate at the ends. The striae are comprised of fine lineolate areolae; areolae are 50-80 in 10 µm. Distinctive annula are present at the poles. The annulae are comprised of one to four transapical striae that interrupt the typical striae. The raphe is straight and filiform, with straight proximal ends. Terminal raphe ends are deflected. An isolated punctum may be present, or it may be absent, in the central area.
Geissleria includes species that were formerly included in the ‘Annulatae’ section of Navicula, including Navicula paludosa (Hustedt) and N. similis Krasske. Geissleria species are found in oliogotrophic to eutrophic waters, but are locally rare in abundance. The genus includes over 70 taxa, which are widely distributed across Europe, Asia, South America, North America and the Maritime Antarctic and sub-Antarctic. Geissleria species have been recorded in a range of freshwater habitats, including rivers, lakes, springs, splash zones, and soils (Novais et al. 2013). Species level ecological preferences may be more specific.
Cite This Page:
Spaulding, S., and Edlund, M. (2009). Geissleria. In Diatoms of the United States. Retrieved February 26, 2017, from http://westerndiatoms.colorado.edu/taxa/genus/Geissleria