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. 251 squamatic acid strain is more frequent. However, there are only sparse collections from northern Lapland and from most Russian regions. The chemotype with both squamatic and thamnolic acids has been found from many provinces, but relativelymany of them (four) have been collected fromLaatokan Karjala. Small amounts of squama- tic acid in addition to thamnolic acid, or vice versa , would presumably be found more frequently in HPLC analyses. The strain containing thamnolic and ± alectorialic acids is the main chemotype of Usnea subfloridana in most parts of Europe, e.g., in Estonia (P. Halonen & T. Randlane, unpubl.), Norway (Krog et al. 1994), and the British Isles (James et al. 1992). Remarks . Usnea subfloridana is close to U. was- muthii , but the latter has more often longitudinal cracks at the base and its soralia become more fre- quently slightly excavate and elongated. Further- more, U. wasmuthii has on average a thinner me- dulla and a thicker central axis, and it has a differ- ent chemistry with barbatic and/or salazinic acids or very rarely usnic acid alone. However, Clerc (1991) did not find any differences in the thick- ness of the medulla between these two species. Ecology . The species has been collected main- ly from Betula (34%), Picea (25%) and Alnus (11%), and less frequently from Pinus , Sorbus , Salix , Populus , Prunus , Tilia , Quercus , Acer , La- rix , Juniperus , lignum and rocks (in total 548 spec- imens). Usnea subfloridana has a wide ecologi- cal amplitude from humid and relatively shady forests to open inhabited sites, although it avoids very dry localities. Distribution . Finland: 1–21; Russia: 1–8, 10– 12. World distribution: widespread from north- ern boreal to temperate areas (Halonen et al. 1998). Usnea subfloridana is the most common shrubby Usnea in mesic and moist forests in most regions of East Fennoscandia. The species occurs in every province of Finland, but it has not been found in northernmost parts of the Murmansk Region. Selected specimens examined . — Finland . Uusimaa. Lapinjärvi (Lappträsk), Hardom, Lindnäs, 1956 Klingstedt (H), strain 1. Etelä-Savo: Hirvensalmi, Kirjala, 1917 Linkola (H), strain 2. Etelä-Pohjanmaa: Raippaluoto (Replot), Norra Vallgrund, 1957 Bäck (H), strain 2. Pohjois-Savo: Pielavesi, Säviä, Kallioselkä, 1947 Huuskonen (Räsänen, Lichenoth. Fenn. no. 244, H, OULU), strain 1. Oulun Pohjanmaa: Oulu, Välivainio (Siirtola), 1911 Huumonen (OULU), strain 3. Sompion Lappi: Sodankylä, Riesto 3.5 km WSW, Jäkälä- maa, 1959 Ahti 10192 (H), strain 2. Enontekiön Lappi: Enon- tekiö, Muotkajärvi, 1992 Puolasmaa (TUR), strain 1. Inarin Lappi: Inari, Ivalo, E of the village, 1936 Ahlner (S), strain 2. Russia . Leningrad Region. Isthmus karelicus: Zeleno- gorsk (Terijoki), Puhtula, 1938 Fagerström (H), strain 2. Republic of Karelia. Karelia ladogensis: Kurkijoki, Otsan- lahti, 1932 Räsänen (Räsänen, Lich. Fenn. Exs. no. 13, TUR, sub U. fulvoreagens ), strain 1. Karelia transonegensis: Vod- lozero National Park, Lake Vodlozero NE, 1991 Vitikainen 12529 (H), strain 1. Murmansk Region. Regio kuusamoën- sis: Kutsa Nature Reserve, Nivajärvi, 1994 Halonen (OU- LU), strain 1. Lapponia Imandrae: Kumzha River, near Kaita Mt., 1996 Petrova (KPABG), strain 1. 8. Usnea substerilis Motyka Wydaw. Muz. Slask. Katowicach, Dzial 3, 2: 24. 1930. — Type: Italy (‘Austria’). Bolzano (Bozen), Gröden (Groeden), St. Ulrich, above Unterkoffel, 1899 Arnold , Lich. Exs. no. 1538b (W, lectotype, n.v. , designated byMotyka 1936:291; H!, H-NYL p.m. 1371!, isolectotypes). Chemistry: usnic, salazinic, barbatic and 4- O -demethylbarbatic acids (isolecto- type in H). Usnea sorediifera Motyka, Wydaw. Muz. S l a sk. Kato- wice, Dzia l 3, 2: 24. 1930, nom. illeg. [ non Usnea soredii- fera (Arnold) Lynge 1921, see Usnea glabrata ]. — Type: Italy. Bocche, on Larix , Zopf , Krypt. Exs. Mus. Vindob. no. 1555 (UPS!, lectotype, here designated; B, BP, W, iso- Fig. 7. Expanded soralia of Usnea subfloridana Stirt. with some isidia. From 1994 Halonen (OULU). Scale = 0.5 mm.