Notes on Arthrorhaphis and Its Lichenicolous Fungi in Greenland

Abstract

Three yellow colored Arthrorhaphis-taxa (Arthrorhaphis alpina, A. citrinella, and A. vacillans) are floristically treated for Greenland. A key and a distribution map are included. In addition, short descriptions are provided for these taxa as well as for three lichenicolous fungi on Arthrorhaphis Cercidospora soror, C. trypetheliza, and Merismatium decolorans, all of which are reported as new to Greenland. The taxa of the genus Arthrorhaphis in Europe and Greenland have previously been revised by Obermayer (1994). Ihlen (1998) treated the Norwegian taxa. Three species-Arthrorhaphis alpina, A. citrinella, and A. vacillans-all of them yellow-colored due to the occurrence of rhizocarpic acid, were recognized for Greenland. The last-mentioned species (syn. Bacidia anziana Lynge) has also been discussed by Lynge (1940) and Hansen and Poelt (1987). A map outlining the distribution of Arthrorhaphis vacillans and A. alpina in the American Arctic has recently been presented by Thomson (1998). With the intention of mapping the Greenland occurrences of these species in detail, we investigated the available material. The four non-yellow (rhizocarpic acid lacking) species of Arthrorhaphis, A. aeruginosa R. Sant. & Tensberg, A. grisea Th. Fr., A. muddii Obermayer, and A. olivacea R. Sant. & Tensberg have so far not been found in Greenland. MATERIAL AND METHODS About 200 specimens from the herbaria c and GZU (including representative material of duplicates from herbarium o) have been studied with Zeiss light microscopes. The cited material is kept in c and GZU. KEY TO THE SPECIES OF ARTHRORHAPHIS CONTAINING