Range Extensions for Some Cryptogams from Granite Outcrops in Alabama

Abstract

Two granite outcrops in the Piedmont of east-central Alabama yield- ed two moss species new to the state and a range extension of 320 km for a lichen. Pleurochaete squarrosa, thought to be restricted to calcareous substrates, is re- ported from a granitic rock outcrop 160 km south of its previously known range in the Interior Low Plateaus and Valley and Ridge Province. Pleurozium schreberi, a boreal moss that extends through the Appalachian Mountains into North Car- olina, is found 240 km to the south at an elevation of only 248 m. Cladina evansii is also reported from the Piedmont, 320 km disjunct from its typical localities in maritime forests or sandhills of the Coastal Plain. We urge more intensive col- lecting of plants from granite outcrops throughout the Southeast before these sites are destroyed. Exposures of granitic rock occur in the Piedmont of the southeastern United States from southern Virginia to eastern Alabama. These areas, consisting of unbroken expanses of bare rock that range in size from a few square meters to hundreds of hectares, have long been of interest to botanists. They present environmental conditions strikingly dif- ferent from those of the surrounding countryside and to which a unique and largely en- demic flora has adapted. McVaugh (1943) first reported the locations of the larger granite outcrops in the South- east and mapped the distributions of many characteristic species. In his catalogue of species, which included cryptogams, McVaugh (1943) noted a relationship between the outcrop flora and the flora of the western U.S. and northern Mexico. Walters and Wyatt (1982) examined the floristic relationship between outcrops in Texas and those in the Southeast and concluded that affinities are more clearly expressed between genera, rather than species, and that life-form spectra for the two areas are nearly identical and decidedly desertic. In Alabama, plants from granitic outcrops were listed by Harper (1939), and Mohr (1901) and Wilkes (1965) have compiled checklists for the bryoflora of the state. Although the flowering plants characteristic of granite outcrops have drawn a great deal of attention, relatively little interest has focused on the cryptogams. Cladonia caro- liniana Tuckerm. was first collected from a granite outcrop by Lewis David von Schwei- nitz, who lived in Salem, North Carolina from 1812 to 1822 (McVaugh 1943). Keever (1957) carried out ecological studies of the establishment of Grimmia laevigata (Brid.) Brid., a pioneer on bare rock. Orthotrichum keeverae Crum & Anderson (Crum & An- derson 1956) and Riccia dictyospora Howe (McVaugh 1943) were first collected from granite outcrop localities in North Carolina and Georgia, respectively. As part of a larger survey of the cryptogams of granite outcrops in the Southeast, we have made recent collections in Alabama. This paper reports two mosses new to Alabama and a range extension of 320 km for a lichen. Voucher specimens of the following species have been deposited in the herbarium of Duke University (DUKE): 007-2745/82/405-409$0.65/0