Monographs Details: Microcoleus acutissimus 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:Phormidiaceae
Description:Species Description - Filaments small and relatively straight, 400-550 µ long, 20-35 µ diam., containing 15-30 trichomes, closed at the conical tips when young, later opened and the trichomes extruding; trichomes straight, almost parallel in the sheath, not constricted at the cross-walls, long and very sharply acuminate at the apices; 1.8-2.2 µ diam.; cells pale aeruginous, homogeneous, 2-4 times as long as the diam.; apical cell longer and very sharp, conical; cross-walls obscure; sheath hyaline, irregular along the margin, somewhat mucous.

Distribution and Ecology - Growing on a church wall, Sabana Grande, no. 952 d, type; on the soil, between Hatillo and Arecibo, no. 1366 b; on a wall in Fort San Cristobal, San Juan, no. 1991 e.

Discussion:

PLATE 11, FIGURE 2

The nearest approach in relationship to this species of Microcoleus, so far as is known, seems to be M. tenerrimus Gomont, a salt-water species. The plants of that species are larger, of a deeper color, and especially not so long and sharply attenuated at the apices.