Monographs Details: Hassalia brevis
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 100-130 µ long, 8.5-10.5 µ diam., densely matted together forming a thin, pannose stratum; mostly straight or arcuate in part; trichome frequently separated at the heterocyst, forming numerous short filaments; cells 7.2-8.4 µ diam., dolioform, about one-half the diameter long; heterocysts numerous, compressed-spherical, golden-colored; sheath very thin, smooth and hyaline; branches short, 50-70 µ long.
Distribution and Ecology - Growing on a concrete fountain in Fajardo, no. 659, type; on trees, Coamo Springs, no. 300 c; on old wood at Hacienda Catalina, Palmer, no. 747; Laguna Tortuguero, no. 864; on loose rock about seven kilometers east of Coamo, nos. 1869 b and 1870 f.
PLATE 18, FIGURE 40
Practically all of the material at hand of this species of Hassalia is in the hormogonial stage, the filaments having separated at the heterocysts by the decay of the delicate sheath at that point. There are a few branches intact, however, that show clearly the rupture of the sheath and the filament emerging just below the heterocyst. The sheath decomposes at a very large percentage of the heterocysts, whether branches arise there or not, leaving the whole mass of filaments broken, and the heterocysts all basal on the trichomes.