Notes on the Genus Usnea Dill. Ex Adanson

Abstract

Usnea quercma Bystrek & Gorzyriska, based on heterogeneous type material, is lectotypified and becomes a synonym of U. vjirthii P. Clerc. Usnea wirthii is new for South America. A distribution map of U. madeirensis Motyka (Syn.

The lichen genusUsnea(Parmeliaceae) in tropical South America: species with a pigmented medulla, reacting C+ yellow

“…Usnea ceratina shares a similar morphology, medullar pigmentation and range of chemotypes with U. entoviolata. It differs in the ontogeny and morphology of soralia (Clerc 2004): in U. ceratina soralia grow from the top of tubercles, thus they are distinctly stipitate, and they bear numerous isidiomorphs. Soralia eventually fuse or enlarge almost to the branch diameter, but in that case they are convex, and they remain distinctly stipitate (never becoming excavate) and of irregular outline (not circular).…”

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

“…Both corticolous and saxicolous, moderately acidophilous, anitrophilous and moderately toxitolerant (Wirth 1980), U. subscabrosa displays a south-western European-Macaronesian-NE American disjunction (Clerc 1992;Esslinger & Egan 1995;Clerc & Herrera-Campos 1997). In Europe, it has been reported from several localities, from Portugal and the British Isles to Yugoslavia; it is known also from South America (Clerc 1997). In the Iberian Peninsula, it has been reported by numerous authors.…”

“…It is relatively resistant to air pollution (Wirth 1980;Kauppi & Halonen 1992). Usnea hirta is a species of worldwide distribution (Clerc 1997;Halonen et al 1998). In Europe, it has been reported from boreal areas to Mediterranean mountains (Wirth 1980;Clauzade & Roux 1985;Nimis 1993;Halonen & Pulasmaa 1995).…”

“…Recently, several studies have focused on the systematics of European species of Usnea (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.…”

“…Naturalist 6: 107 (1881). U. marocana Motyka (Clerc 1994(Clerc , 1997 Taxonomy. A detailed description of this mainly North American species is given in Clerc (1994).…”