Novel fern- and centipede-like Selaginella (Selaginellaceae) species and a new combination from South America.

Two new Selaginella species (i.e. S. altheae Valdespino and S. squamulosa Valdespino) and a novel combination [i.e. S. philipsonii (Jermy & Rankin) Valdespino] from South America are proposed. Descriptions, illustrations (line drawings and scanning electron micrographs, SEM, images), discussion on taxonomic affinities and information on habitat, distribution and phenology, as well as on conservation status are provided for each. Selaginella altheae is morphologically similar to species with erect, fern-like habit placed in the " Selaginella flabellata (L.) Spring group" as defined by Hieronymus, while S. squamulosa is allied to a species assembly with centipede-like habit here informally termed the " Selaginella vernicosa Baker group;" whereas S. philipsonii with its moss-like habit may be associated with species in the " Selaginella jungermannioides (Gaudich.) Spring group" or those centered on S. ovifolia Baker. All taxa here proposed are classified in subg. Stachygynandrum .