The Lichen Bryoria subdivergens (Dahl) Brodo & D. Hawksw. in Greenland and North America

Abstract

Bryoria (Dahl) Brodo & D. Hawksw., formerly known only from its type locality in southwest Greenland, has now been found in several new sites in western Greenland as well as in an alpine community in the Bitterroot Mountains of Montana, USA. The species is compared with two other members of Bryoria sect. Subdivergentes: B. abbeviata (Miill. Arg.) Brodo & D. Hawksw. and B. oregana (Tuck. ex Nyl.) Brodo & D. Hawksw., and is found to be distinct from both. Of the five sections of the genus Bryoria, the section Subdivergentes (Mot.) Brodo & D. Hawksw. is certainly the most distinctive. The dull, red-brown colour, longitudinally foveolate branches, and especially the knobby, jig-saw puzzle-like cortical cells are found in all four known species: B. abbreviata (Miill. Arg.) Brodo & D. Hawksw., B. oregana (Tuck. ex Nyl.) Brodo & D. Hawksw.-both from western North America, B. (Dahl) Brodo & D. Hawksw., a terricolous tundra species, and B. diverges- cens (Nyl.) Brodo & D. Hawksw., a corticolous species known only from southeast Asia (Hawksworth 1970; Brodo & Hawksworth 1977). In preparing the revision of and its allied genera, Hawksworth and Brodo were able to reexamine almost all the material named as Alectoria subdivergens used as the basis of North American reports of the species. They found that all these specimens were misidentified, and concluded that B. was still known only from the type locality in southwest Greenland. Since 1977, several new specimens of this species have been found, which necessitates an expansion of the description of the species pre- sented by Brodo & Hawksworth (1977) as well as a reevaluation of its distribution. The first good specimen studied from other than the type locality was collected by Alstrup on Disko Island and reported in a recent paper (Alstrup 1979). It agrees well with the type except that it is longer and sterile, resembling B. oregana more closely than it does B. abbreviata (thus in disagreement with what was stated by Brodo & Hawksworth 1977: 153). A more complete description of the locality and its vegetation together with three other new localities for the species in Greenland was given by Alstrup (1979). Ad- ditional localities from west Greenland are now known, thanks to an old collection that has been found in the Botanical Museum in Copenhagen (c) and to more recent collections made by Alstrup. One of these recent specimens (Alstrup 69478) had numerous sorediate branches (Fig. 1-2). The soralia are of the modified fissural type, similar to those described for the sorediate morphotype of B. trichodes (Michx.) Brodo & D. Hawksw. (Brodo & Hawks-