Ann.฀Bot.฀Fennici฀41:฀27–35฀ ISSN฀0003-3847 Helsinki฀27฀February฀2004฀ ©฀Finnish฀Zoological฀and฀Botanical฀Publishing฀Board฀2004 Comparison฀of฀morphological,฀anatomical฀and฀chemical฀ characters฀in฀Pseudocyphellaria฀endochrysa฀and฀P.฀ vaccina฀(Lobariaceae,฀lichenised฀Ascomycota) Jarle฀W.฀Bjerke฀&฀Arve฀Elvebakk Department฀of฀Biology,฀Faculty฀of฀Science,฀University฀of฀Tromsø,฀N-9037฀Tromsø,฀Norway Received฀29฀Jan.฀2003,฀revised฀version฀received฀27฀Mar.฀2003,฀accepted฀10฀Apr.฀2003 Bjerke,฀J.฀W.฀&฀Elvebakk,฀A.฀2004:฀Comparison฀of฀morphological,฀anatomical฀and฀chemical฀char- acters฀ in฀ Pseudocyphellaria฀ endochrysa฀ and฀ P.฀ vaccina฀ (Lobariaceae,฀ lichenised฀ Ascomycota).฀ —฀Ann.฀Bot.฀Fennici฀41:฀27–35. A comparison of morphology, anatomy and chemistry of the two closely related lichens Pseudocyphellaria endochrysa and P. vaccina is presented. The presence of a scabrid-areolate upper surface in P. vaccina and a minutely pubescent, non-scabrid upper surface in P. endochrysa have been used as key characters for distinguishing the two species. However, the present study shows that in exposed habitats, such as in alpine habitats of southern South America and in low antarctic tundra on South Geor- gia, P. endochrysa also has a scabrid-areolate upper surface, almost without any hairs. In more protected sites, the upper surface of P. endochrysa is more pubescent and not scabrid. Previous reports of P. vaccina from the treeless zones in southernmost South America and the South Atlantic islands are referable to P. endochrysa. This conclusion is also supported by anatomical and chemical characters. Analyses by HPLC and TLC showed that pseudocyphellarins A and B, calycin, pulvinic dilactone and pulvinic acid are the principal lichen substances in P. endochrysa. In P. vaccina, pseudocyphellarin A is generally in minor amounts only, and pseudocyphellarin B was not detected. The three pulvinic acid derivatives are present in yellow-medullary thalli of P. vaccina. Distribution maps are presented. While P. endochrysa is very rare north of 50° south- ern latitude, P. vaccina is common north to 37°S. Key words: HPLC, lichens, Pseudocyphellaria, taxonomy Introduction A few of the many southern South American species of Pseudocyphellaria are also known from the Falkland Islands and South Geor- gia in the South Atlantic. Pseudocyphellaria endochrysa, a broad-lobed and yellow-medul- lary species, has been reported several times from these islands, e.g. from South Georgia by Huneck et al. (1973, 1984), Lindsay (1973, 1974) and Galloway (1986, 1992), and from the Falkland Islands by Delise (1825), Cotton (1915), Dodge (1965, as P. latilobia) and Gallo- way (1986, 1992). Other members of the genus that have been reported from South Georgia are P. freycinetii (Huneck et al. 1973, 1984, Lindsay