Flora of North America species comparison

In North America, Grimmia trichophylla is principally a lowland species, occurring in the mountains up to about 1000 m., rarely higher. In the Southern Hemisphere, it may be found up to 4000 m. In New Zealand, the species is common, and in contrast to G. trichophylla in North America, frequently bears capsules. The New Zealand plants are usually smaller than American specimens, and the leaves are frequently contorted. The nearly cosmopolitan G. trichophylla has many phenotypes, and numerous subspecies and varieties have been described. In damp and shaded habitats, the awns may be short, just as in dry unfavorable habitats at high altitudes, where stunted specimens may occur with small, short leaves and reduced awns, or even with muticous leaves. Grimmia trichophylla has frequently been confused with related species such as 36. G. muehlenbeckii and 34. G. lisae (see discussions thereunder for identification details). Robust forms of G. trichophylla have been mistaken for G. austrofunalis (H. C. Greven 1997, 2003), which does not occur in North America. Although some of those plants have leaves of equal length along the stem, characteristic of G. austrofunalis, they also have both leaf margins recurved, and the medial and outer basal laminal cells are longer and more robust than in that species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Of conservation concern.

Grimmia americana is a rare endemic, currently known only from three sites. Until 1999, the species was known only from its type locality in Jeff Davis County of western Texas. A second locality was reported by J. Muñoz (1999) in Arizona and a third site by L. R. Stark et al. (2002) in Nevada. Thus, it is reasonable to expect G. americana to occur also in southern New Mexico. It is recognized as a member of subg. Grimmia by its immersed, ventricose capsule, with a short mitrate calyptra and eccentric seta attachment. The overall habit of the species also is similar to that of the other members of the subgenus. However, its basal laminal cells are thick-walled while other members have thin cell walls. H. A. Crum (1994c) implied that G. americana is similar to G. anodon, but the former is readily separated by its fully developed, perforated peristome, rostellate operculum, and thick-walled basal laminal cells. Grimmia crinitoleucophaea, also most commonly found in the American Southwest, is dioicous, has a rudimentary peristome, and thin-walled basal laminal cells.

(Discussion copyrighted by Flora of North America; reprinted with permission.)