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.)

Grimmia funalis is frequently misidentified because it is extremely variable in height, color, and length of the awns. In optimal conditions, it forms extremely dense, grayish green cushions that break up easily into clusters and straight single plants. A distinctive feature is the string-like appearance of the dried-up shoots, which results from the spiral twisting of the leaves around the stem. However, Greven has also seen populations without such spirally twisted leaves. Under the microscope, the mid leaf areolation with yellowish, short-rectangular, very thick, and sinuose cell walls is characteristic. The formerly recognized taxa G. calvescens, G. imberbis, and G. ryanii are actually male plants of G. funalis. They grow in separate cushions with muticous to short-awned leaves, deviating greatly from the much taller, long-awned female plants. These male plants might be confused with G. elongata, which frequently grows in the same habitat, or with G. caespiticia. However, in G. elongata the basal cells are pellucid, straight, and thin-walled or only slightly incrassate. In G. caespiticia the basal cells are shorter, tending to be quadrate to short-rectangular, and the leaf apex is cucullate.

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