Micrasterias borgei var. borgei Willi Krieg.

Micrasterias borgei var. borgei Willi Krieg.

( Fig. 4B, C View FIG )

Die Desmidiaceen Europas mit Berücksichtigung der aussereuropäischen Arten. (Dr. Rabenhorst’s Kryptogamen-Flora von Deutschland, Österreich und der Schweiz: 13). Vol. 2: 86 ( Krieger 1939).

DISTRIBUTION. — South America and China. Amazon Basin: Grönblad (1945); Scott et al. (1965); Förster (1969, 1974); Thomasson (1971); Uherkovich & Rai (1979); Melo et al. (2005); Souza de et al. (2007); Melo & Souza de (2009); Melo et al. (2009); Cadima (2013); Cunha de et al. (2013); Feitosa et al. (2015). Western Amazonia (lowlands): Krieger & Scott (1957); Araujo (2003); Ortega et al. (2007).

DESCRIPTION

Cells 264.1-278.0 µm long, 235.0-243.5 µm wide, isthmus 32.0-38.2 µm, apex 53.5-58.5 µm; cells 1.1 times longer than wide.Cells with deep median constriction, central sinus closed, slightly open at ends; cell wall finely punctuated, with a number of spines in the middle of the basal part of the semicells, just above the isthmus, with a row of intramarginal spines along the median sinus, others on each side to the left along the deepest incisions. Semicells five-lobed, robust; polar lobe with a deep sinus, a little more than half its length; incisions between lateral lobes open and deep, U- or V-shaped; lateral lobes with consecutive bifurcations to apex, slightly curved denticles, apex divided into two divergent two-denticulated lobules, central denticles slightly oriented towards the sinus; polar lobe larger and more robust than lateral lobes.