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 shastae is known only from Mt. Shasta. Its discovery demonstrates that the bryoflora of California is still not fully known. It also shows that the state is exceptionally rich in endemic species of Grimmia: G. mariniana, G. nevadensis, G. serrana, and G. shastae. Because of its abundantly present gemmae on the adaxial surface of the distal lamina, the latter is not likely to be confused with any other species of the genus. While gemmae are not rare in Grimmia, they are usually produced on leaf tips (G. anomala, G. hartmanii), on the abaxial side of the leaf (G. torquata, G. trichophylla), or in leaf axils (G. trichophylla, G. muehlenbeckii). In no other Grimmia species are gemmae produced in clusters on the surface of the adaxial lamina at the distal part of the leaf. The position of the species within the genus is not clear. Although its leaf form and areolation demonstrate its similarity to G. tergestina (subg. Litoneuron), the longitudinal plicae in the most distal leaves align it with G. caespiticia (subg. Guembelia). Sinuose laminal cell walls, characteristic of Grimmia, are only weakly present.

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