Monographs Details: Rivularia flagelliformis 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 - Thallus globose to irregular, very soft and gelatinous or mucilaginous in consistency, about 1 cm. diam.; trichomes a considerable distance from each other, constricted at the dissepiments throughout except the terminal hair in the juvenile stage, but on nearing maturity the condition disappearing except with a few cells at the base, up to 1 mm. long, 5.5-6.8 µ diam. at the base before spore formation begins, tapering gradually from the base to the apex, terminating in a long hair 1-1.8 µ diam.; cells granular, aeruginous, mostly quadrate, hair cells 4-6 times as long as broad; heterocysts hyaline, mostly spherical, 11-14 µ diam., others vary from ellipsoidal to conical; sheath undulate, hyaline, visible for about 80 µ, then vanishing into the common transparent gelatinous tegument; spores densely congested with very fine granules, 11-14 µ diam., up to 80 µ long.

Distribution and Ecology - Growing in a water reservoir near Rio Piedras, no. 126, type.

Discussion:PLATE 14, FIGURE 25