Didymodon rigidulus
Didymodon rigidulus:
Southeastern Alaska Distribution: Known only from Juneau (Holzinger and Frye, 1921).
[as B. icmadophila] Known only from near the Mendenhall Glacier, Juneau Area (Persson, 1963).
Habitat: In calcareous situations, on rocks, soil, boulders, walls, and so forth.
[as B. icmadophila] The southeastern Alaska material came from chlorite schist cliffs. Elsewhere the species is known from wet rocks, and on stones beside streams or waterfalls in calcareous districts.
Comments: Subspherical gemmae are usually present. The species is essentially absent in the bulk of mountainous and oceanic eastern Asia.
[as B. icmadophila] The southeastern Alaska collection was fertile. This species appears to be exceedingly rare in North America outside Arctic regions. The total range of this species is somewhat unusual. It has the appearance of a circumboreal distribution, but is missing not only from the eastern portions of Asia, but from eastern North America as well. It could also be considered a western North America - western Europe disjunct which extends eastward well into Asia.
