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

Species description:
Genus named to honour G.R. Andreae a German apothecary in the 18th century; the species derived from the habitat: rock.

Reproduction:
Sporophytes black or dark red-brown, relatively fre­quent, maturing in spring or, at high elevations, after snow melt.

Distinguishing characteristics:
Any dark brown to black moss that forms tufts of tiny plants on plane rock surfaces (rather than in crevices) is likely to be Andreaea. With opened sporangia, when dry, the genus is very characteristic since the four or more longitudinal openings gape to release spores.

Habit:
Forming black to dark red-brown tufts or cushions.

Similar Species:
There are ten species of Andreaea in the province; four resemble A. rupestris and are not readily distinguishable without micro­scopic examination and experience. The other five, A. blyttii, A. nivalis, A. megistospora, A. rothii, and A. schofieldiana have a distinct midrib. The largest is A. nivalis in which the leaves are usually strongly curved and reddish to brown, the plants are usually more than 50 mm long and soft, while A. rupestris rarely has stems as long as 10 mm and stems are brittle. A. nivalis is usually at higher elevations and most frequent in late snow areas. A. blyttii forms short black turfs over rocks in late snow areas.