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

ANN. BOT. FENNICI 36 (1999) • Usnea in East Fennoscandia. III. 247 present only on young soralia, but tuberculate soralia may have spinules. Chemistry . Strain 1 ( n = 167): usnic + salazinic + norstictic acids ± other compounds of the stictic acid group ± protocetraric acid (trace) (K+ yel- low, orange or red, PD+ yellow or orange); strain 2 ( n = 35): usnic + norstictic acids ± other com- pounds of the stictic acid group (K+ yellow, or- ange or red, PD+ yellow or orange); strain 3 ( n = 7): usnic acid (K–, PD–). The strain with only usnic acid, which is also represented by Usnea extensa subsp. gemina , has not previously been reported to occur in U. glabrescens . Clerc (1992) found menegazziaic and psoromic acids in U. gla- brescens in the British Isles, but those compounds have not been found in the East Fennoscandian material. Remarks . The “type” for Usnea barbata var. glabrescens indicated by Motyka (1936: 300) is not a type, because it is not cited in the protologue. The species is closely related to U. fulvoreagens ( see the comments under the species). Ecology . The species has been collected mainly from Betula (34%), Picea (29%) and Alnus (15%), and less frequently from Pinus , Sorbus , Populus , Salix , Prunus , Larix , Juniperus , lignum and rocks (in total 190 specimens). The species occurs in various forests, but it avoids dry sites, and it is relatively less frequent in inhabited areas than U. fulvoreagens and U. wasmuthii , for in- stance. Distribution . Finland: 1–17, 19; Russia: 1–3, 5–8, 10, 11. World distribution: incompletely cir- cumpolar from northern boreal to temperate re- gions. Widely distributed in Europe, but south of Fennoscandia it is mostly found in alpine and ± continental areas (Motyka 1936, Wirth 1995). Usnea glabrescens has a wide distribution in East Fennoscandia being rare in northern regions. It is locally quite common especially in the central parts of Finland, but it is less frequent than U. hir- ta , U. subfloridana and U. lapponica , and the pen- dent species U. filipendula Stirt. Selected specimens examined . — Finland . Uusimaa: Espoo, Nuuksio (Nouks), Långträsk, 1934 Linkola (H), strain 3. Etelä-Savo: Luumäki, 1965 Takala 1524 (H), strain 2. Pohjois-Savo: Kaavi, Peuramäki, 1941 Räsänen (H), fer- tile, strain 1. Pohjois-Karjala: Tohmajärvi, 1914 Oesch (H), strain 1. Keski-Pohjanmaa: Kälviä, Ruotsalo, Pirskeri, 1933 Auer (TUR), strain 1. Koillismaa: Kuusamo, Toranginaho, 1960 Ahti 11879a (H), strain 1. Sompion Lappi: Sodankylä, Korvanen, 1958 Ulvinen (OULU), strain 3. Russia . Lenin- grad Region. Isthmus karelicus: Zelenogorsk (Terijoki), Puhtula, 1938 Fagerström (H), strain 1. Republic of Karelia. Karelia borealis: Korpiselkä, Ägläjärvi, 1929 Räsänen (H), strain 2. Karelia pomorica occidentalis: Kuusijärvi, Pokon- vaara, 1942 Huuskonen (H), strain 1. Murmansk Region. Regio kuusamoënsis: Kutsa area, Tuorusjoki, 1925 Linkola (H), strain 2. Lapponia Imandrae: Cape Turii, 1967 Dom- brovskaya (KPABG), strain 2. 5. Usnea hirta (L.) F. H. Wigg. Prim. Fl. Holsat. 91. 1780. — Lichen hirtus L., Sp. Pl. 1155. 1753. — Type: Sweden. Fries, Lich. Suec. Exs. no. 150 (UPS!, holotype, conserved type proposed by Jørgensen et al. 1994: 377, accepted by Gams 1996: 309; the neotypifi- cation by Motyka 1936: 86 and Bystrek 1994b: 20 was thus devalidated). Chemistry: usnic acid and murolic acid group. Usnea variolosa Motyka, Usnea 1: 104. 1936. —Type: USA. NewMexico, Hermit Peak near Las Vegas, corticola, 1930 Brouard (LBL, holotype) — see Clerc (1997: 211). Further synonyms of the species are given by Halonen and Puolasmaa (1995). Thallus erect, rarely subpendent or pendent, usually small, to ca. 6(–15) cm long, often richly branched. Branching mostly anisotomic-dichoto- mous. Branches slender, to ca. 1(–1.5) mm in diam., often angular with foveoles and depres- sions. Annular cracks sparse to relatively abun- dant, often ± constricted. Base pale to brownish. Cortex thin to relatively thin, 6– 8 –10% ( n = 18). Medulla generally lax and thick, 19– 27 –32% ( n = 18). Central axis usually relatively thin, 21– 31 – 46% ( n = 18). Papillae normally absent (seen in only one specimen, which may be a hybrid), but minute tubercles are common. Fibrils usually nu- merous near the base and sparse at apices. Soralia or soralia-like structures minute, may occasion- ally develop on scars when isidia become de- tached; soredia farinose. Isidia usually abundant and tall, spinule-like, occurring both singly and in clusters, and they grow also near apices and often along low ridges. See figures of Usnea hirta in Halonen and Puolasmaa (1995) and Halonen et al. (1998). Chemistry . Strain 1 ( n = 54): usnic acid + murolic acid group (K–, PD–); strain 2 ( n = 9): usnic + norstictic (normally very low amounts) acids + murolic acid group (K+ yellow, orange or red, PD+ yellow or orange); strain 3 ( n = 8): usnic