Grimmia pulvinata is a member of the family Grimmiaceae. According to a system of classification suggested by Buck and Goffinet, Grimmiaceae is placed in the order Grimmiales. Grimmiales is in turn is circumscribed by the subclass Dicranidae and the class Bryopsida (Buck et al. 2000).

Grimmia pulvinata is found throughout northern temperate regions of the world. Within the United States, G. pulvinata is primarily found in western states and a few isolated places in the midwestern region.

Grimmia pulvinata grows in dense small clusters often appearing cushion-like. It is acrocarpous in habit, in that its sporophyte is produced at the terminal end of main or secondary branches. The leaves are tipped with hyaline cells, which give them a distinctly gray, or hoary appearance. The seta are usually bowed. The capsules often appear to be creased with longitudinal ridges.

Grimmia pulvinata, like other members of the genus, grows primarily on a substratum of exposed rock. G. pulvinata seems to prefer rocks which are more alkaline. Their affinity for rock as a substratum is makes them important early colonizers during primary succession of bare rock.

A recent study performed by Ugur, Ozden, Sac and Yener (2003) explored the possibility of using G. pulvinata, among other mosses and some lichens, as a bio-indicator of ²¹⁰Po and ²¹⁰Pb deposition as a result of the release of ²²²Rn into the atmosphere. The study concluded that G. pulvinata is a very promising candidate for biomonitoring such deposition due to its relative abundance in the study area (western Turkey) and its sensitivity to such chemicals.

Literature Cited
Buck, William R. and Bernard Goffinet. "Morphology and Classification of Mosses" in Bryophyte Biology. A. Jonathan Shaw and Bernard Goffinet eds. New York: Cambridge University Press, 2000.
Ugur, A., B. Ozden, M.M. Sac, and G. Yener. "Biomonitoring of 210Po and 210Pb using lichens and mosses around a uraniferous coal-fired power plant in western Turkey" Atmospheric Environment. Volume 37 (2003): 2237-2245.

Written by Bryan Eppert 2003