University of Oulu

Studies on the lichen genus Usnea in East Fennoscandia and Pasific North America

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Author: Halonen, Pekka1
Organizations: 1University of Oulu, Faculty of Science, Department of Biology
Format: ebook
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.1 MB)
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Language: English
Published: Oulu : University of Oulu, 2000
Publish Date: 2000-01-10
Thesis type: Doctoral Dissertation
Defence Note: Academic Dissertation to be presented with the assent of the Faculty Science, University of Oulu, for public discussion in Kuusamonsali (Auditorium YB 210), on February 11th, 2000, at 12 noon.
Reviewer: Docent Tiina Randlane
Docent Soili Stenroos


The shrubby Usnea species of East Fennoscandia and the whole known Usnea flora of British Columbia were studied. Furthermore, the status and distribution of Usnea hirta and U. longissima, which have divergent habitat requirements and distribution patterns, were surveyd in East Fennoscandia. The two species also occur in British Columbia and their chemistry, ecology and distribution were compared in the two study areas. The nomenclature and taxonomy of U. hirta were also revised.

Nine shrubby Usnea species were documented from East Fennoscandia and 25 species and species groups were recorded from British Columbia (when U. fulvoreagens and U. pacificana are included as distinct species). U. chaetophora, U. diplotypus and U. nidulans s. lat. were reported as new to North America, whereas U. esperantiana and U. rigida s. lat. were documented for the first time for Canada, and U. ceratina and U. rubicunda are new to British Columbia. U. pacificana was described as a new species from the Pacific Canada and the United States and U. wasmuthii was reported from the states of Washington and Oregon as new to North America. Several taxa were recognized as synonyms and lectotypified in our studies.

In total, 21 secondary medullary substances or compound groups were found in the East Fennoscandian and 24 in the British Columbia Usnea species. Salazinic acid is the most common substance in both areas. New chemotypes were found in three shrubby Usnea species in East Fennoscandia and in six taxa in British Columbia. Differences in the chemistry of some species were found when comparing the East Fennoscandian and British Columbia specimens, e.g., in U. hirta and U. longissima.

All the East Fennoscandian Usnea species studied have a relatively southern distribution or they are infrequent in northern regions, while most of the surveyed North American species have more or less maritime distribution. All these Usneae are primarily epiphytes and the majority of them prefer well-lit and moist sites.

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Series: Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
ISSN: 0355-3191
ISSN-E: 1796-220X
ISSN-L: 0355-3191
ISBN: 951-42-5524-0
ISBN Print: 951-42-5523-2
Issue: 340
Copyright information: © University of Oulu, 2000. This publication is copyrighted. You may download, display and print it for your own personal use. Commercial use is prohibited.