Anomodon minor (Musci: Leskeaceae) in North America

Abstract

Anomodon minor (Hedw.) Furnr. is reported from a disjunct locality in northeastern Alberta, Canada. Its occurrence in eastern North America, with disjunct populations in the south- western United States and Mexico, is mapped. One of us recently collected Anomodon minor in northeastern Alberta along the Clearwater River floodplain at 56042'N, 110*08'W (Lee, June 30, 1983--ALTA, CANM, UBC). The species occurs there on sheltered clifffaces ofthe Middle Devonian Methy formation outcrops, which are hard, buff-colored, porous dolomites. The general vegetation of the area is dominated by scrubby, open Populus tremuloides Michx. with Betula papyrifera Marsh., Pinus bank- siana Lamb. and Picea glauca (Moench) Voss in- termixed in the canopy. Understory vegetation is highly variable within short distances, reflecting the rugged topography. Moist sheltered draws have 100% plant cover dominated by Linnaea borealis var. americana (Forbes) Rehd., Mitella nuda L., Ledum groenlandicum Oeder and by feather moss- es, particularly Hylocomium splendens (Hedw.) B.S.G. The drier, exposed summits of the outcrops have only 30% plant cover dominated by Juniperus communis L., Elymus innovatus Beal, Ditrichum flexicaule (Schwaegr.) Hampe and Pleurozium schreberi (Brid.) Mitt. Bryophytes commonly found on the cliff faces and crevices include Hypnum cu- pressiforme Hedw., Encalypta procera Bruch, Thui- dium abietinum (Hedw.) B.S.G., Rhytidium rugo- sum (Hedw.) Kindb., Ditrichum flexicaule