Plants very small, delicate, often branching. Stems ca. 1.5--3 mm. Stem leaves 0.3--0.4 mm, serrulate, apex rounded; costa ending at midleaf; distal medial cells 14--18 µm in width, 1--2:1, papillae 1--2 per lumen. Specialized asexual reproduction occasional, by elliptic gemmae. KOH laminal color reaction negative, yellow or black.

Sporophytes not seen in area of flora. Limestone, phosphate rock; 0--40 m; Fla.; Mexico (Guerrero, Tamalipas, Veracruz), West Indies; South America (Brazil, Ecuador in Galapagos).

This species is restricted in the range of the flora to four counties in Florida: Alachua, Dade, Jackson and Marion. As discussed previously (R. H. Zander 1993), I disagree with placing G. orcuttii into the synonymy of the Asian G. vernicosa (J. D. Hooker) M. Fleischer (P. L. Redfearn 1991). The American material is more robust and is fairly consistent but not totally so in its usually larger leaf cells (14--18 µm wide) and 1--2 papillae per lumen (rather than 12--14 µm wide and 1 papilla per lumen). The genus needs revising.