Micrasterias borgei var. aequalis Willi Krieg.

Micrasterias borgei var. aequalis Willi Krieg.

( Fig. 4A 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. Amazon Basin: Martins (1986b). Western Amazonia (lowlands): Araujo (2003).

DESCRIPTION

Cells 172.7-217.0 µm long, 159.1-193.0 µm wide, isthmus 25.0-31.7 µm; apex 52.0-53.0; cells 1.1 times longer than wide. Cells subcircular in outline, deep median constriction; five-lobed semicells with acute, angular incisions. Hyaline cell wall. Semicells with spines located along the margins of the median sinus and on the margins of lateral and basal lobes and lobules. Polar lobe protruding from the lateral lobes, polar lobes opening gradually towards apex, protruding angles, two-denticulated, curved, divergent; lateral lobes of approximately equal size, each divided into two lobes by a deep incision, each subdivided by three incisions in four parts, with two denticles.

REMARKS

This variety is distinguished from the type variety by the similar development of their lateral and basal lobes, in which both show divisions up to third order lobules. Instead, M. borgei var. borgei show differences between the lateral and basal lobes, with the former developing up to fourth order lobules ( Bicudo & Sormus 1982). Compared with Micrasterias sanctipaulensis C.E.M.Bicudo & L.Sormus, M. borgei var. aequalis is larger in size and has spines on the cell wall while the first has a glabrous cell wall ( Bicudo & Sormus 1982).