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 nevadensis is a rare but locally abundant endemic, known only from the Sierra Nevada Mountains. Fertile specimens of it can be separated from G. mariniana by the absence of peristome teeth and by the chestnut brown capsules. Gametophytically, specimens of G. nevadensis contrast with those of G. mariniana by having a uniform basal areolation of short-rectangular cells with thin lateral walls, and margins not hyaline. If fertile, the immersed, eperistomate capsules will separate G. nevadensis from G. ovalis, G. alpestris, and G. montana. Sterile specimens can be separated from G. alpestris by the absence of bulging cells, and the uniformly short-rectangular, thin-walled basal laminal cells. While both G. nevadensis and G. montana have plane to incurved distal margins and both lack bulging laminal cells, the uniformly short-rectangular, thin-walled basal laminal cells and concave leaves will identify G. nevadensis. The latter is easily separated from G. arizonae and G. pilifera, in contrast with which it lacks stomata and peristome teeth, and its concave leaves with plane to incurved margins differ markedly from the keeled leaves with recurved leaf margins of the others.

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