Monographs Details: Hassalia rugulosa
Authority: Gardner, Nathaniel L. 1927. New Myxophyceae from Porto Rico. Mem. New York Bot. Gard. 7: 1-144. pl. 1-23.
Family:Microcystaceae
Scientific Name:Hassalia rugulosa
Description:Species Description - Filaments 150-250 µ long, very much contorted, forming a dense, flocculent stratum one-fourth to one-third mm. thick, black on being dried, 14.5-17.5 µ diam.; branching single under the heterocysts, rarely geminate; trichomes 6-9 µ diam.; broadest at the apices, narrowest at the bases; cells pale blue-green, one-half to one-third as long as the diameter at the apices, and torulose, quadrate or longer in the older parts and almost cylindrical; heterocysts usually a little wider than the adjacent cells; subspherical to very much compressed, 2-5 µ long; sheath 3.5-5 µ thick, homogeneous, dark brown, roughened on the surface with fine irregular granules.

Distribution and Ecology - Growing on rocks by the road near San Lorenzo, no. 517, type.

Discussion:

PLATE 19, FIGURE 45

The very much contorted habit and the secretion of granules on the sheath, coupled with the combination of other characters mentioned above distinguish this species of Hassalia.