Monographs Details: Stigonema scytonematoides N.L.Gardner
Authority: Gardner, Nathaniel L. 1927. New Myxophyceae from Porto Rico. Mem. New York Bot. Gard. 7: 1-144. pl. 1-23.
Description:Species Description - Filaments relatively short and straight, 125-175 µ long, 23-27 µ thick, sparsely branched; branches similar to the main frond, blunt and rounded; cells uniseriate, compressed-spherical, when old and dried drawn out somewhat at the poles, showing distinct protoplasmic connections, bluish-green, homogeneous, 11-13 µ diam.; heterocysts similar to the cells in shape, size, and form; sheath thick, subgelatinous, faintly lamellose, particularly so toward the apices where the laminae turn outward and backwards from several cells, yellowish brown; hormogonia short and blunt.
Distribution and Ecology - Growing on red earth north of Maricao, no. 1250, type; on red earth near Mayagiiez, no. 880 e; on rocks by the road north of Maricao, nos. 1245, 1250, and 1253 a; on rocks between Utuado and Adjuntas, no. 1643; on rocks, Arroyo de.los Corchos, no. 1715.
PLATE 22, FIGURE 57
It is somewhat troublesome to distinguish the above new species of Stigonema from certain species of Hassalia. There are many filaments in both genera which do not show branching. Both have heterocysts very similar, being formed from an original cell of the filament, whereas in many species of the genus Stigonema for the most part the heterocyst is formed from a part of an original cell produced by a longitudinal division. It can readily be distinguished, of course, when the branching can be observed, and especially by the short, blunt, hormogoniferous branches. Stigonema scytonematoides seems closely related to S. elegans of this paper. The sheath is wider and lamellose, the cells are more nearly spheres in form, and the diameter of the filament is greater than in that species.