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.
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.



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.