The genus Oncophorus in Britain and the addition of O. integerrimus Hedenäs to the British flora

Abstract

ABSTRACT Introduction. Currently there are two species of Oncophorus recorded in Britain O. virens (Hedw.) Brid. and O. wahlenbergii Brid., both uncommon species of wet, upland sites which are at least moderately calcareous. In a revision of Scandinavian material, Hedenäs divided O. virens into two species, O. virens and O. integerrimus, and described two further species, O. elongatus and O. demetrii previously referred to O. wahlenbergii. Methods. Herbarium specimens of all British Oncophorus species from the Royal Botanic Garden Edinburgh (E) the National Museum of Wales, Cardiff (BBSUK, NMW) and the Natural History Museum (BM), plus material from the author’s own herbarium were examined and re-determined using Hedenäs’ descriptions. Results. None of the vouchers checked proved to be either O. elongatus or O. demetrii but in addition to O. virens and O. wahlenbergii some of the vouchers belonged to O. integerrimus so this species is added to the British list. The key features for distinguishing the three species are described. Conclusions. In Britain all three species have similar habitat preferences, usually occurring above 600 m and reaching as high as 1000 m a.s.l. on Ben Lawers. They most frequently occur in a turf, often with other bryophytes and sedges, in flushed ground at the edge of springs or below crags, where the bedrock is at least moderately calcareous and most sites are associated with calcareous schist or limestone. There is little change in the pattern of distribution as a result of the re-determinations and Oncophorus virens remains the only English species.