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

Pekka Halonen

Department of Biology

Abstract

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.

Table of Contents

Acknowledgements

Abbrevations of herbaria

List of original papers

1. Introduction

1.1. Taxonomy
1.2. Morphology
1.3. Secondary chemistry
1.4. Ecology
1.5. Distribution

2. Material and methods

3. Results and discussion

3.1. Taxonomy
3.2. Morphology
3.3. Secondary chemistry
3.4. Ecology
3.5. Distribution

4. Conclusions

References

List of Tables
1. Main secondary medullary metabolities in the genus Usnea in East Fennoscandia and Pacific North America. The North American data is mainly based on the British Columbia material, except Usnea fulvoreagens and U. wasmuthii (see comments ³ and ⁴). E-FEN = East Fennoscandia, P-AM = Pacific North America, ¹ = the occurrence in East Fennoscandia is not studied, ² = unpublished data, ³ = the material is mainly from the United States, ⁴ = all specimens are from the United States, * = the species was not found from East Fennoscandia, + = present in all specimens examined, ± = present in some specimens (chemoraces), a = accessory substance, not important for taxonomy and often present in small amount to faint traces, ^S = present only in soralia, ^H = the strain may be a hybrid. ATR = atranorin, BAE = baeomycesic acid, BAR = barbatic a., CNSTI = connorstictic a. (seemingly overlooked in the studied material and it was excluded in IV), Cph-1 = convirensic a., Cph-2 = confumarprotocetraric a., CPSO = 2’-O-demethyl-psoromic a., CRSTI = cryptostictic a., CSTI = constictic a., DBAR = 4-O-demethyl-barbatic a., DIF = diffractaic a., EVE = evernic a., FAT = fatty acids (bourgeanic acid in U. esperantiana, the murolic acid complex in U. hirta and usually caperatic acid in U. lapponica), FUM = fumarprotocetraric a., MEN = menegazziaic a., NSTI = norstictic a., PRO = protocetraric a., PSO = psoromic a., SAL = salazinic a., SQU = squamatic a., STI = stictic a., THA = thamnolic a.
2. The systematic grouping of the shrubby Usnea species occurring in Fennoscandia by Clerc (1987a) and Halonen et al. (III, IV). ¹ = not treated by Halonen et al. (III, IV), since the species has not been found in East Fennoscandia and Pacific North America, but it is probably not a member of the Usnea fragilescens agg., ² = not treated by Clerc (1987a), ³ = a synonym of U. glabrescens (III), ⁴ = represents an unidentified pendent species (III), ^? = the systematic status of the species is not clearly indicated by Clerc (1987a).

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