Monographs Details: Scytonema milleri var. majus 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 forming small tufts or a continuous stratum about 4 mm. thick, densely packed together, erect, very flexuous, 20-25 µ diam.; cells slightly dolioform at the apices of the trichomes, cylindrical in the older parts, one-half to one-third the diameter long at the apices, mostly quadrate in the older parts; branching and heterocysts sparse; sheath thick, firm, dark brown, homogeneous.

Distribution and Ecology - Growing on rocks by a stream near Maricao, no. 1166, type.

Discussion:The measurements given by Forti15 for the filaments of S. Milleri are 15-21 p in diameter. The material distributed in the copy of "Wittrock, Nordstedt and Lagerheim, Alg. Exsic, no. 1511, at the Farlow Herbarium, Harvard University, determined by Flahault, measures 12-15 \x in diameter. The material described above resembles no. 1511 (loc. cit.) very much, but is larger in all of its parts. It is close to some forms of S. guyanense, but has a firm, homogeneous sheath, and the material is thoroughly mature.