Local distribution of Usnea species are related with contrast Buryatia republic climatic conditions. 10 species have been revealed, geographical tendency in species distribution is presented as occurring in the Buryatia. Revision according by own and herbaria materials of IGEB SB RAS, Ulan-Ude (UUH) and the Komarov Botanical Institute, Saint-Petersberg (LE). Morphology and anatomy studied by standard methods with a light microscope, a dissecting and scanning electronic microscopes. Secondary metabolites explore by Thin-layer Chromatography. At least 2 sample from every species to different sites taken. HPTLC was performed follow by Orange [15], using “Sorbfil” plates in solvent system A and C and acetone extract from thalli fragments. In some samples chemistry explored by HPLC on Agilent 1200 chromatograph. All samples with most commom chemotypes of lichen substances represent. A practical identification key for 10 species of genus Usnea (Parmeliaceae) for Buryatia Republic provided. Key based on external characters, and will be useful for “quick” determination, but chemotaxonomic features although important. Key illustrated and provided with glossary of the main terms. The most important distinguishing features of Usnea should be considered estimation and types of soralia and presence/absence of isidia, form and color of holdfast, branching and form of secondary branches, details of inner structure. Fibrills and papilla density also very important, but can be varied by environmental condition. In drought condition adaptive ectomorphs образуются to extreme environmental factors as drought and high radiation.

1. Imetkhenov A.B. (ed.). Atlas Buryatii [Atlas of Buryatia]. Moscow, Federalnaya sluzhba geodezii i kartografii Rossii Publ., 2000, 48 p. (in Russian).

2. Budaeva S.E. Annotirovannyi spisok lishainikov Respubliki Buryatiya. [Annotated List of Lichens of Republic of Butyatia]. Ulan-Ude, BGSKhA Publ., 2012, 181 p. (in Russian).

3. Golubkova N.S. Rod Usnea Dill. ex Adans. [Genus Usnea Dill. ex Adans.]. Opre-delitel' lishainikov Rossii. [Handbook of the Lichens of Russia]. St. Petersburg, 1996, vol. 6, pp. 62-105. (in Russian).

4. Krasnaya kniga Respubliki Buryatiya. Redkie i nakhodyashchiesya pod ugrozoi ischeznoveniya vidy zhivotnykh, rastenii i gribov. [The Red Data Book of Republic of Buryatia: Rare and Endangered Species of Animals, Plants and Fungi]. Ulan-Ude, Buryat Scientific Center SB RAS Publ., 2013, 688 p. (in Russian).

5. Anenkhonov O.A. (ed.). Opredelitel' rastenii Buryatii [Handbook of plants of Buryatia]. Ulan-Ude, 2001, 672 p. (in Russian).

6. Urbanavichene I.N., Urbanavichyus G.P. Lishainiki Baikal'skogo zapovednika (annotirovannyi spisok vidov) Ser. “Flora i fauna zapovednikov” [Lichens of Baikal’sky reserve (annotated species list). Flora and fauna of reserves Series], vol. 68, Moscow, 1998, 55 p. (in Russian).

7. Urbanavichene I.N., Urbanavichyus G.P. K flore lishainikov khrebta Khamar-Daban (yuzhnoe Pribaikal'e) [To lichen flora of Khamar-Daban Range (southern Prebaikalia)]. Nov. sist. nizsh. rast. [Novitates systematicae plantarum non vascularum], 1999, tomus XXXIII, pp. 161–171. (in Russian).

8. Urbanavichene I.N., Urbanavichyus G.P. Dopolnenie k flore lishainikov Baikal'skogo zapovednika. II [Addition to lichen flora of Baikal’sky reserve. II]. Nov. sist. nizsh. rast. [Novitates systematicae plantarum non vascularum], 2001, vol. XXXV, pp. 205-208. (in Russian).

9. Urbanavichyus G.P. Spisok likhenoflory Rossii [A Checklist of the Lichen Flora of Russia]. St. Petersburg, 2010, 194 p. (in Russian).

10. Kharpukhaeva T.M. Lishainiki Dzherginskogo gosudarstvennogo prirodnogo zapovednika [The Lichens of Dzherginsky Nature State Reserve]. Ulan-Ude, Buryat Scientific Center SB RAS Publ., 2010, 156 p. (in Russian).

11. Kharpukhaeva T.M. Vidy roda Usnea (Parmeliaceae) v Respublike Buryatiya [Species of genus Usnea (Parmeliaceae) in Republic of Buryatia]. Nov. sist. nizsh. rast. [Novitates systematicae plantarum non vascularum], 2011, tomus XLV, pp. 257-267. (in Russian).

12. Clerc P. Systematics of the Usnea fragilescens aggregate and its distribution in Scandinavia. Nordic J. Bot., 2007, vol. 7, no. 4, pp. 479-495.

13. Goward T. The Lichens of British Columbia. Illustrated Keys. Part 2, Fruticose Species. Vancouver, 1999, 319 p.

14. Halonen P. Studies on the genus Usnea in East Fennoscandia and Pacific North America. Acta Universitatis Ouluensis, A Scientiae Rerum Naturalium, 2000, vol. 340, pp. 1-29.

15. Feige G.B., Lumbsch H.T., Huneck S., Elix J.A. Identification of Lichen substances by a standardized high-performance liquid chromatographic method. J. Chromatogr. A, 1993, vol. 646, no. 2, 3, pp. 417–427.

16. Orange A., James P.W., White F.J. Microchemical Methods for the Identification of Lichens. British Lichen Society, 2001, 101 p.

17. Ohmura Y. Taxonomic study of the genus Usnea (lichenized Ascomycetes) in Japan and Taiwan. J. Hattori Bot. Lab., 2001, no. 90, pp. 1–96.

18. Halonen P., Myllys L., Ahti T., Petrova O. The lichen genus Usnea in East Fen-noscandia. III. The shrubby species. Ann. Bot. Fenn., 1999, vol. 36, pp. 235-256.

19. Torra T., Randlane T. The lichen genus Usnea (lichenized Ascomycetes, Par-meliaceae) in Estonia with a key to the species in the Baltic countries. The Lichenologist, 2007, vol. 39, no. 5, pp. 415-438.