The Lichen Genus Usnea On Quercus Suber In Iberian Cork-Oak Forests

Abstract

(Clerc 1984a(Clerc , b, 1987a(Clerc , b, c, 1991(Clerc , 1992(Clerc , 1994(Clerc , 1997(Clerc , 1998Myllys 1994; Halonen & Puolasmaa, 1995;Halonen 1997) and have provided valuable information on this difficult genus of fruticose lichens, so that accurate identification of especially SW European species is now possible. Usnea species are frequent and abundant in cork-oak forests on Quercus suber, where they attain a high degree of coverage on branches and a scattered growth on boles. The lack of updated studies on the systematics, floristic and ecology of the genus Usnea in Spain prompted us to focus on this genus.Quercus suber is a Western Mediterranean endemic, distributed both in Europe and North Africa. It occurs preferentially in siliceous areas with a warm Mediterranean climate with oceanic influence. Its distributional area covers a total of 2-35 M Ha, of which about 1-18 M Ha are found in Spain and Portugal (Montoya 1988). Cork-oak forests are mainly distributed in the south-west of the Iberian Peninsula, although scattered localities are numerous, including the Catalonian (Barcelona and Girona) and Valencian (Valencia and Castellon) areas. The cork oak can be found in several biogeographic provinces, in the thermo-and mesomediterranean vegetation belts with dry to hyperhumid ombroclimates (terminology of bioclimatic zones follows Rivas-Martinez 1987). This biogeographical and bioclimatological

The lichen genus Usnea (lichenized Ascomycetes, Parmeliaceae) in Estonia with a key to the species in the Baltic countries

“…The treatment of chemotypes also varies by different authors (Purvis et al 1992;Halonen et al 1999;Fos & Clerc 2000). The chemistry of this species is very variable but in many cases the presence of norstictic acid can be used as a diagnostic character.…”

“…Since U. hirta prefers acid bark (Fos & Clerc 2000), it grows mainly on conifers (36% of specimens examined on Pinus, 34% on Picea, 10% on other) and lignum (9%); deciduous trees are seldomly colonized by this species. Since U. hirta prefers acid bark (Fos & Clerc 2000), it grows mainly on conifers (36% of specimens examined on Pinus, 34% on Picea, 10% on other) and lignum (9%); deciduous trees are seldomly colonized by this species.…”

“…Altogether five chemotypes have been recorded in U. wasmuthii (Clerc 1992;Halonen et al 1999;Fos & Clerc 2000;Ohmura 2001). Altogether five chemotypes have been recorded in U. wasmuthii (Clerc 1992;Halonen et al 1999;Fos & Clerc 2000;Ohmura 2001).…”

“…For example, U. fulvoreagens, with a general suboceanic distribution pattern (Halonen et al 1999;Fos & Clerc 2000) is also recorded from the southeastern region of Estonia which is locally the most continental area and Usnea lapponica, with a continental distribution (Clerc 1992) is known throughout Estonia, including northern coastal regions. For example, U. fulvoreagens, with a general suboceanic distribution pattern (Halonen et al 1999;Fos & Clerc 2000) is also recorded from the southeastern region of Estonia which is locally the most continental area and Usnea lapponica, with a continental distribution (Clerc 1992) is known throughout Estonia, including northern coastal regions.…”

Synopsis of Usnea (lichenized Ascomycetes) from the Azores with additional information on the species in Macaronesia

“…Mies (1993) listed 13 species in the Cape Verde Islands. Taking into account modern treatments of this genus (Clerc 1987a(Clerc , 1992James et al 1992;Halonen et al 1998Halonen et al , 1999Fos & Clerc 2000) and removing the doubtful taxa we should actually be closer to 25 species known to occur in Macaronesia: 10 species in the Azores, 20 species in Madeira, 20 species in the Canary Islands and 10 species in the Cape Verde Islands (P. Clerc unpublished). Moberg & Purvis (1997) considered Usnea as a genus ''badly in need of revision where it is probable that further taxa remain to be described''.…”