Micrasterias radiosa var. radiosa Ralfs

Micrasterias radiosa var. radiosa Ralfs *

( Fig. 5F View FIG )

The British Desmidieae: 72 ( Ralfs 1848).

Micrasterias sol Ehrenberg ex Kützing , Species algarum: 171 ( Kützing 1849).

DISTRIBUTION. — Cosmopolitan. Amazon Basin: Förster (1969); Lopes & Bicudo (2003); Gutiérrez & Cadima (2004); Cadima (2013); Cunha de et al. (2013). Western Amazonia (lowlands): no records.

DESCRIPTION

Cells 159.0-162.2 µm long, 157.3-158.0 µm wide, isthmus 15.2-18.3 µm, apex 42.3 µm; cells as long as they are wide. Cells with a deep median constriction, central sinus almost entirely closed, opening only at the ends. Semicircular semicell, five-lobed; polar lobe with linear incision until near of the isthmus; slightly open and deep between the polar lobes; lateral lobes with consecutive bifurcations; polar lobe with V-shaped sinus, apex divided into two divergent lobules two-denticulated, polar lobe with the same size as the lateral lobes. Very deep lobular incisions between polar lobes and lateral lobes, and between lateral lobes and basal lobes.

REMARKS

Specimens analyzed here are morphologically consistent with the descriptions, drawings, and pictures shown by Förster (1969) and Lopes & Bicudo (2003) for the Amazon, Bicudo & Sormus (1982) for São Paulo, and Santos et al. (2016) for Bahia in Brazil.