Monographs Details: Hapalosiphon subgelatinosus 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 - Erect filaments numerous, sparsely branched, arising from a more or less creeping filament, 10-14 µ diam., 200-250 µ long, nearly straight and parallel, in part attenuated, adhering to each other somewhat by their subgelatinous sheaths into small fascicles; creeping filaments larger than the erect filaments; cells variable in shape and in size, cylindrical to dolioform, 5-10 n diam., the constrictions at the dissepiments extending to the sheath, homogeneous, pale aeruginous; sheath hyaline, thick, homogeneous; heterocysts conspicuous, slightly yellowish brown, subspherical, mostly in the creeping filaments and in the lower part of the erect filaments, 8-10 µ diam.

Distribution and Ecology - Growing on limestone between Arecibo and Utuado, no. 1476 f, type.

Discussion:PLATE 23, FIGURE 61