The Lichen Genus Pertusaria in the Falkland Islands (Islas Malvinas)

Abstract

Eight species of the genus Pertusaria are found in the Falkland Islands (Islas Malvinas), two of which are here described as new: P. malvinae Messuti & A. W. Archer and P. salacinifera Messuti & A. W. Archer; P. alterimosa Darb., P. cerebrinula Zahlbr., P. erubescens (Hook. & Taylor) Nyl., P. macloviana Miill. Arg., P. perrimosa Nyl., and P. spegazzinii Miill. Arg. are reported from Falkland Islands. A key to the named species of Pertusaria on the Falkland Islands is given. The Falkland Islands or Islas Malvinas* are the largest island group situated in the South Atlantic Ocean, between latitudes 40o-60oS, 500 km east of the Strait of Magellan. Two main islands (West Falklands and East Falklands)* and about a hundred islets form the Falkland Islands (Cabrera 1994; Imshaug 1969). The climate of these islands is cool and moist with snow during most of the year. According to Cabrera (1994) these islands are included in the phytogeographical area named Provincia Insular (Regi6n Antlirtica o Austral, Dominio Subantirtico). The islands have been visited by a number of scientific expeditions, but few have contributed to our knowledge of the lichen flora. During the 19th century and the first years of the 20th century, many expeditions visited the Falkland Islands and collected lichens, bryophytes, and vascular plants. In 1968, the U.S. Antarctic Research Program financed an expedition that included lichenologists (H. A. Imshaug and R. C. Harris). Over 2,000 collections were made and a total of 235 species were recorded in a preliminary study (Imshaug 1969). The lichen genus Pertusaria in the Falkland Islands (Islas Malvinas) has received little attention. Until 1950, seven taxa in the genus were reported from the islands (Grassi 1950). This account is based on specimens collected by H. A. Imshaug and R. C. Harris during the 1968 expedition and on examination of the type specimens of the relevant species. The eight Pertusaria species described are all saxicolous (with the exception of P. erubescens and P. macloviana which are rarely corticolous on the Falkland Islands) and all the species lack cortical xanthones. This is unusual as, for example, P. lophocarpa Korber, which contains 4,5-dichlorolichexanthone, is found on Maquarie Island (Australia) and Campbell Island (New Zealand), both of which are in approximately the same latitude as the Falkland Islands (Archer 1997). This study has revealed a number of undescribed or poorly known taxa which are reported here. MATERIALS AND METHODS Specimens from the herbaria AAS, B, BM, CANB, CHR, CTES, EGR, ESS, G, GZU, H, H-NYL, LE, LPS, MSC, S, TU, and w were examined. Microscopy.-The techniques used for the examination of specimens have been described previously (Archer 1991). Sections of the fruiting bodies were mounted in water for measurement of the spore size. Chemistry-The chemical constituents were identified using thin layer chromatography (TLC) (Archer 1993; Culberson 1972) and gradient-elution high performance liquid chromatography (HPLC) (Elix et al. 1997; Feige et al. 1993). RESULTS AND DISCUSSION 1. PERTUSARIA ALTERIMOSA Darb., Wiss. Erg. Schwed. Sudp. Exped. IV, Liefr. 11: 7. 1912.