E-Flora BC: Electronic Atlas of the Flora of British Columbia

Species description:
Genus named in honour of F.J.C. Grimm, a German physician and botanist. Species name describing the cushion-like habit

Reproduction:
Sporophytes common in late winter to early spring; when immature the seta arches and the sporangium is buried, mouth downward, among the leaves. Sporangia are grooved when mature and dry.

Distinguishing characteristics:
The rounded, greyish cushions and the curved seta that arches so that sporangia are often buried, mouth downward in the cushion, plus the grooved sporangia, are usually enough to distinguish this species.

Habit:
Forms rounded, grey-green cushions in which both the dried leaves and white hair points contribute to the grey-green effect.

Similar Species:
See Coscinodon catyptratus. From similar species of Grimmia, G. putvinata is not easy to distinguish. From G. trichophylla, the tufted habit, when present, is usually distinctive; unfortunately this feature is not consistent. In G. trichophylla, the hair point tapers gradually to the body of the leaf and forms less than 1/4 of the leaf length; in G. putvinata the hair point tapers abruptly and is 1/3 – 1/2 the length of the leaf. Several high-elevation species of Grimmia are similar but their setae are not curved nor are the mature sporangia grooved. Tortuta muratis grows in a similar habitat but plants are usually not tufted, sporangia are erect, long-cylindric and peristome teeth are spirally twisted.