(Grunow) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella subaequalis var. florentina Grunow in Van Heurck 1880
SYNONYM(S): Cymbella aequalis var. florentina (Grunow) Cleve 1894 | Cymbella florentina (Grunow) Mills 1934
REPORTED AS: Cymbella subaequalis (Lange-Bertalot and Metzeltin 1996, figs. 94: 24, 25)
Contributor: Loren Bahls - January 2014
Length Range: 36.1-64.3 µm
Width Range: 7.9-11.9 µm
Striae in 10 µm: 11-15 at the valve center, 16-19 near the apices on the dorsal side
Valves are lanceolate and moderately dorsiventral. The dorsal margin is arched and the ventral margin is less strongly arched with a gibbous middle. Apices are rounded and not protracted. The axial area widens gradually from the apices towards the central area, together forming a narrow lanceolate space. The central area is formed by a shallow depression on the dorsal side. The raphe is lateral. Proximal raphe ends are filiform, deflected towards the ventral margin, and tipped with slightly expanded pores. Distal raphe ends are hooked towards the dorsal side. Striae are radiate throughout, more strongly radiate near the apices. Areolae in the striae number 22-24 in 10 µm at the valve center, and are closer together towards the apices where they approach 30 in 10 µm.
Basionym: Cymbella subaequalis var. florentina
Author: Grunow in Van Heurck 1880
Length Range: µm
Striae in 10 µm:
Cleve, P.T. (1894). Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26(2):1-194, 5 pls.
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Lange-Bertalot, H. and Metzeltin, D. (1996). Indicators of oligotrophy - 800 taxa representative of three ecologically distinct lake types, Carbonate buffered - Oligodystrophic - Weakly buffered soft water. Lange-Bertalot, H. (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 2. Ecology, Diversity, Taxonomy. Koeltz Scientific Books. Königstein, Germany, 2:390 pp.
Van Heurck, H. (1880). Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers.
Cymbopleura florentina has been recorded from several lakes, ponds, and fens in the northern Rocky Mountains and northwestern Great Plains of Montana. Here pH ranges from 7.3 to 9.5 and specific conductance ranges from 140 to 1500 µS/cm. Krammer (2003) reports C. florentina from “oligotrophic lakes in the Alps and from the Balkans with a moderate electrolyte content”, also from “Finnish Lapland and from smaller waters in the plains”.
Big Therriault Lake, Ten Lakes Scenic Area, Kootenai National Forest, Montana: home of Cymbopleura florentina.
Credit/Source: Loren Bahls