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 attenuata resembles forms of the extremely variable Racomitrium heterostichum (= Bucklandiella heterosticha), and because G. N. Jones (1933) mentioned five varieties of the latter, it is not surprising that in some herbaria, e.g. NY, all specimens of G. attenuata have been filed as varieties of R. heterostichum. In 1898, Kindberg realized that his species is not a Racomitrium, but a Grimmia, and wrote: “Habit of G. elatior.” In spite of Kindberg’s correct transfer to Grimmia, T. C. Frye (1917–1918) synonymized G. attenuata with R. macounii. Adding to the confusion, H. A. Möller (1929) synonymized it with G. elatior, and J. Muñoz (1999b) cited it as G. arcuatifolia, which is a synonym of G. lisae. Grimmia elatior is characterized by ellipsoid striate capsules, leaf margin broadly recurved on just one side, and an opaque 2-stratose distal lamina with rounded usually mammillose to papillose cells, the mid leaf cells quadrate to short-rectangular with slightly sinuose, thick walls. Like Grimmia leibergii, G. attenuata is characterized by its elongate to linear, strongly nodulose and thick-walled basal juxtacostal cells, its extremely thick-walled and sinuouse medial cells, leaf margins both recurved, and stem central strand absent. However, the two differ in costa shape and basal marginal cell shape.

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