Petrova O. The lichen genus Usnea in eastern Gennoscandia. III Shrubby species. Ann. Bot. Fennici. 1999, 36, p. 235-256.

248 Halonen • ANN. BOT. FENNICI 36 (1999) acid (K–, PD–). Murolic acids may be present in every specimen but sometimes in very lowamounts and thus they may have not been found in TLC studies. As pointed out by Klingstedt (1965), the strain containing norstictic acid (i.e. K+ and PD+ specimens) is more common in eastern parts of Finland. In our TLC studies we indeed found only one specimen from western parts of Finland (Ou- lun Pohjanmaa). Remarks . According to Clerc (1992), Usnea foveata Vain. is a synonym of U. hirta , while By- strek (1994a) regards it as a distinct species. Our opinion is that it probably is a representative of the polymorphic Usnea scabrata Nyl. s. lato. The type material of U. foveata is difficult indeed, since it has characters which may occur both in U. hirta and U. scabrata s. lato , i.e. a thin cortex, a lax medulla, sausage-like segments of branches, abun- dant foveoles and the chemistry with usnic acid alone. Usnea foveata bears only relatively sparse short isidia and scars of them, however, while long and abundant isidia on a mature thallus is one of the most diagnostic morphological characters of U. hirta . Usnea foveata also is pendent and weakly papillate, and it has been cut into many fragments, which are up to 18 cm long, and fragments have been distributed in several herbaria (at least in H, LBL, S-Motyka and TUR-V). Recently Bystrek (1994b) reviewed the status of U. hirta in Europe, also citing many Finnish and Russian specimens. The treatment contains many nomenclatural inac- curacies, however, and we do not accept the nine infraspecific taxa that were recognized by him. Ecology . The species has mainly been col- lected from Pinus (51%), lignum (12%), Betula (12%) and Picea (12%), and less frequently from Alnus , Sorbus , Populus , Salix , Juniperus , Prunus , Larix , Quercus , Fraxinus , Acer , Ulmus , Tilia , Rhamnus and rocks (in total 503 specimens). Us- nea hirta is the most xerophytic East Fennoscan- dian Usnea species occurring most frequently in fairly open sites, e.g., in pine forests and bogs. It is relatively pollution-tolerant among Usnea oc- curring even in urban areas (Kauppi & Halonen 1992). Distribution . Finland: 1–21; Russia: 1–4, 6– 8, 10–12. World distribution: the species has been found in almost every continent (Clerc 1997) and it has continental tendencies. This is the only shrubby Usnea species which has been found in every province in Finland in addition to Usnea subfloridana , but its occurrence in the Murmansk Region is poorly known. It is locally the most common Usnea species, e.g., along the coast of the Gulf of Bothnia. Selected specimen examined . — Halonen and Puolas- maa (1995) listed specimens from East Fennoscandia in- cluding southern and northernmost provinces of Finland. The following collection represents the northernmost known locality of Usnea hirta in the Russian Fennoscandia: Mur- mansk Region. Lapponia Imandrae: Khibimy Mts., 1972 Dombrovskaya (KPABG), strain 1. 6. Usnea lapponica Vain. Meddeland. Soc. Fauna Fl. Fenn. 48: 173. 1925 (‘1924’). — Usnea sorediifera Motyka subsp. lapponica (Vain.) Mo- tyka, Wydaw. Muz. S l a sk. Katowice, Dzia l 3, 2: 23. 1930. — Type: Russia. Murmansk Region, Lapponia Imandrae, Lovozero (Lowosersk), in ramulis Abietis ( Picea ), 1887 Kihlman (H!, lectotype designated by Clerc 1987a: 494; S!, isolectotype). Chemistry: usnic and salazinic acids. Usnea arnoldii Motyka, Usnea 1: 288. 1936. — Type: Romania. Carpaty, Czywczyn, SE of Mt. Suligul, 1370 m, ad Fagos , 1935 Madalski (LBL!, holotype). Chemistry: usnic and salazinic acids. [Voucher of the illustration in Motyka (1962: 287): Ukraine, Carpathian Mts. (Wschod- nie), Chernohora (Czarnohora), Pozyzewska, 1934 Motyka (LBL!). Chemistry: usnic and constictic (trace) acids. This specimen represents a pendent morph of Usnea fulvorea- gens .] Usnea hirta (L.) F. H. Wigg. var. dentata Räsänen, Arch. Soc. Zool. Bot. Fenn. Vanamo 3: 178. 1949. —Type: Finland. Varsinais-Suomi, Halikko, Joensuu (Åminne), 1918 Häyrén (H!, holotype). Chemistry: usnic and salazinic acids. —The specimen probably represents a strongly mod- ified Usnea lapponica — see Halonen and Puolasmaa (1995: 134). Thallus erect, rarely subpendent or pendent, to ca. 10(–23) cm long, usually richly branched. Branchingmostly isotomic-dichotomous. Branches normally slender, rarely relatively thick, to ca. 1.3(–1.8) mm in diam., often with foveoles or de- pressions (Fig. 6), apices commonly recurved. An- nular cracks often slightly constricted, rarely with everted medullary tissue. Base pale or shortly brown black to distinctly blackened. Cortex thin to relatively thin, 4– 9 –12% ( n = 42). Medulla usually lax and relatively thick, 10– 19 –32% ( n = 42). Central axis normally relatively thick, 27– 45 –72% ( n = 42). Papillae generally cylindric and numerous. Fibrils fairly sparse tomore often abun-