Monographs Details: Anabaena subtropica N.L.Gardner
Authority: Gardner, Nathaniel L. 1927. New Myxophyceae from Porto Rico. Mem. New York Bot. Gard. 7: 1-144. pl. 1-23.
Family:Nostocaceae
Description:Species Description - Trichomes relatively straight and short, deeply constricted at the dissepiments, 3.5-4.5 µ diam.; cells subcylindrical, approximately quadrate, pale aeruginous to slightly purplish in mass; apical cells blunt, rounded, sometimes smaller than others; heterocysts spherical to subspherical, 5.2-6 µ diam.; spores spherical to slightly longer in part, wall hyaline or somewhat discolored at maturity, smooth, seriate, or discontinuous, developing toward the heterocysts, 5-6.4 µ diam., 6-7.5 µ long.

Discussion:

PLATE 12, FIGURE 9

Aggregated into small masses or free; among other algae in a stream about five kilometers east of Coamo, no. 235 b, type. Two other species of Anabaena were found associated with this one, both, however, sterile, and I have not classified them.