Tiiu Tõrra

The lichen genus Usnea (lichenized Ascomycetes, Parmeliaceae) in Estonia with a key to the species in the Baltic countries

The occurrence of 12 Usnea species in Estonia is verified by investigating c . 1800 specimens. The known distribution and substratum preferences of Usnea taxa in Estonia are summarized. Picea is the main substratum for Usnea species in Estonia, but occasionally these species occur also on deciduous trees, wood, and exceptionally on rock. A key for identification of 16 taxa recorded in the three Baltic countries is provided and diagnostic morphological and chemical characters used in the key are discussed. A new chemotype of U. fulvoreagens has been identified. U. wasmuthii is reported as new to Lithuania.

Phylogenetic relations of European shrubby taxa of the genus Usnea

This study focuses on European Usnea species with sorediate shrubby thalli, with the aim to evaluate the morphological and chemical separation of species in the light of molecular data. Twenty-two Usnea species, including widely distributed taxa such as U. diplotypus, U. fulvoreagens, U. glabrescens, U. lapponica, U. subfloridana, U. substerilis and U. wasmuthii, were included in the study using Bayesian and maximum parsimony analyses of nuclear ITS and beta-tubulin sequences. The analyses showed that: 1) most taxa that are morphologically well delimited are also distinct by means of molecular characters, 2) shrubby taxa in the section Usnea that are difficult to determine by traditional characters form a group of closely related but still genetically distinct entities, except U. diplotypus and U. substerilis which appear to be polyphyletic. The branch lengths differed largely between two parts of the ITS tree (sections Usnea and Ceratinae). Usnea intermedia is proposed as the sexually reproducing counterpart for the sorediate U. lapponica. Additionally, some new chemotypes of Usnea species were determined.

Erratum to: Evaluation of traditionally circumscribed species in the lichen-forming genus Usnea , section Usnea (Parmeliaceae, Ascomycota) using a six-locus dataset

The MycoBank code of the newly described species Usnea parafloridana was missing. The MycoBank code for the species Usnea parafloridana should read: MB818694. Usnea parafloridana K. Mark, Will-Wolf & Randlane sp. nov.; MycoBank No. MB818694. Type: USA, Wisconsin, Vilas Co., Trout Lake Conifer Swamp State Natural Area; 46.0135° N, -89.6586° W; 27.08.2011, Susan Will-Wolf WW14807: isolates WW_018 (holotype, TU; Fig. 4a, c, e), WW_023 (isotype 1, WIS), WW_013 (isotype 2, F). Morphology: thallus shrubby, up to 3–6 cm long, often with relatively few branches; branching mainly isotomic-dichotomous, divergent; lateral branches not narrowed at point of attachment; basal part distinctly jet black, with few annular cracks; papillae verrucose, numerous on main branches and lesser or absent on lateral branches; fibrils few to numerous; soralia small and punctiform when young, enlarging, becoming close to each other but usually staying delimited when mature, more numerous on terminal branches; isidiomorphs numerous, spinulose, relatively short and thick, both on young and mature soralia; cortex thick (9–15%); medulla thin (10.5– 13%), dense, not pigmented; central cord thick (60–73%) and white; apothecia not seen (Fig. 4; colour illustrations in online version). Secondary chemistry: usnic acid in cortex; norstictic acid as a major compound, salazinic acid as an accessory substance (present in most examined specimens) in medulla. Ecology: on branches of Abies balsamea, Larix laricina, Picea mariana, or Pinus strobus in cedar swamp, conifer bog and pine plantation with trees over one-hundred years old. Distribution: currently 15 specimens are known from four localities in Wisconsin, USA. Etymology: the species is morphologically somewhat similar to Usnea subfloridana (both taxa have similar shrubby thalli, black basal parts and delimited soralia with numerous isidiomorphs), which phylogenetically appears conspecific with U. florida. The same root ‘florida’ is used in the epithet of the new taxon to underline this morphological similarity while the prefix ‘para-‘ indicates phylogenetic distinctness of the species from U. florida and U. subfloridana. The online version of the original article can be found at http://dx.doi. org/10.1007/s13127-016-0273-7.

Species Richness of Epiphytic Lichens in Coniferous Forests: the Effect of Canopy Openness

Epiphytic lichen communities were studied in old coniferous forests across Estonia to find out the effect of site openness on the lichen species richness. All lichen species were recorded on the basal 2 m of 105 Picea abies and 105 Pinus sylvetsris trunks. The canopy openness readings were taken with a spherical densiometer around every sampled tree. The number of species on the trunks of both tree species increased significantly with increasing canopy openness. Nine lichen species, e.g. Cladonia cenotea, Lecidea nylanderi, Platismatia glauca, were significantly favoured by higher light availability, and only one species, Coenogonium pineti, by lower light availability. The results demonstrate that in the coniferous forests higher light availability supports higher species richness of epiphytic lichens on the lower trunk of trees.

Impact of alkaline dust pollution on genetic variation of Usnea subfloridana populations

Very little is known whether and how air pollution impacts genetic diversity of lichenized fungi that are well-known indicators of environmental quality. We studied the genetic variation of eight Usnea subfloridana populations in Pinus sylvestris-dominated boreal forest stands in southern Estonia, Northern Europe; four of these populations were exposed to long-term dust pollution released from unpaved road. The mean bark pH of lichen phorophyte differed considerably between polluted and unpolluted forest stands. We genotyped 274 Usnea thalli using nine specific fungal microsatellite markers. Genetic variation measures were calculated and compared between populations from different habitats. Allelic richness, Shannons information index, and genetic diversity of lichen populations were significantly higher in unpolluted forest sites than in polluted forest sites. We conclude that environmental disturbances caused by alkaline dust pollution had negative impact on the genetic variation of U. subfloridana, a common species of lichenized fungi.