The Sphagnum subsecundum complex includes a group of closely related, morphologically intergrading species in section Subsecunda. Nucleotide sequences from six genes (four nuclear and two chloroplast) were obtained from 74 populations representing all the putative species in this complex (S. denticulatum, S. inundatum, S. lescurii, S. subsecundum) to determine if the morphologically-defined taxa represent genetically distinct units. Sampling included populations from North America, Europe, and Asia. Parsimony analyses resolved two major groups of populations, one containing only North American plants (plus one from northern Russia) and the other containing all but two of the European samples, a few from North America, and one from Japan. Two of the four morphospecies occurred in both groups. Shimodaira-Hasegawa (SH) tests indicate that monophyly of S. inundatum, S. subsecundum, and S. lescurii can be rejected, whereas monophyly of S. denticulatum cannot be rejected with our data. Intragenic recombination was detected in both groups of populations, but was substantially higher in the “American” group. Because recombination calls into question the applicability of character-based phylogenetic methods, including parsimony, molecular similarity among populations was estimated using neighbor-joining. Neighbor-joining also resolved geographically correlated groups and corroborated the conclusion that morphologically defined species do not form genetically coherent groups. Groups of populations more closely reflect geographic than morphological patterns.

The ecological amplitudes, associated lichens, and substrates of fifteen regionally rare coastal epiphytic lichens (Bryoria pseudocapillaris, B. spiralifera, B. subcana, Erioderma sorediatum, Heterodermia leucomela, Hypotrachyna revoluta, Leioderma sorediatum, Leptogium brebissonii, Niebla cephalota, Pannaria rubiginosa, Pseudocyphellaria perpetua, Pyrrhospora quernea, Ramalina pollinaria, Teloschistes flavicans, and Usnea hesperina) in 85 randomly-selected and 49 purposively-selected 0.04 ha circular plots along a 5 km wide strip of Pacific coastline from San Francisco Bay to the U.S.-Canadian border are reported. Logistic regression, used to identify environmental variables most indicative of suitable habitat, indicated that small changes in climate and forest type strongly affected probability of occurrence for many species. Threats to coastal lichens, including climate change, are discussed. The findings can be used to aid discovery of additional populations and manage existing habitat.

Treefall gaps are a ubiquitous feature of forested ecosystems and provide regeneration opportunities for many forest mosses which are dependent on microsites created by disturbance. Bryophyte communities on treefall mounds present an excellent opportunity to explore the extent to which community composition is influenced by dispersal patterns and establishment success. The goals of this paper are to 1) determine the bryophyte community structure of treefall mounds in the Adirondack forests and 2) to evaluate the extent to which community structure of treefall mounds is a consequence of dispersal limitation and establishment success and 3) to assess the role of microsite in successful establishment by sown spores and vegetative fragments. Bryophyte communities were described from field census of treefall mounds differing in age class. Most mounds support only 1–2 species, of the possible 13 species that colonize treefall mounds in the study area, the Adirondack Mountains of New York State. Moss species composition and diversity does not change with age of the mound, although cover increases significantly. Experimental treefall mounds varying in substrate and canopy type were created and sown with spores or vegetative fragments of five species: Polytrichum ohioense, Dicranella heteromalla, Atrichum angustatum, Diphyscium foliosum and Pogonatum pensylvanicum. The highest establishment success occurred with fragments sown on humus substrates in canopy gaps. Establishment success was significantly higher when propagules were sown than on the unsown controls. Colonization was very low in the absence of sown propagules. The data suggest that community composition of treefall mounds is strongly influenced by dispersal limitation.

In North America, the common and abundant coastal, corticolous species currently known as Parmotrema rigidum (Lynge) Hale, is shown to be morphologically distinct from the South American type and other South American representatives of the species based on both ascospore and conidial size. We describe the North American taxon as Parmotrema subrigidum Egan sp. nov., recognizing two chemical strains, one with atranorin and alectoronic acid and a second with atranorin, alectoronic, and norstictic acids.

Orthothecium hyalopiliferum is morphologically distinct at the species level from O. intricatum on the basis of its silky soft appearance, the presence of very narrow lanceolate leaves with a leaf tip to leaf base ratio of 1:2 or less; and piliferous leaf tips that end in 3–6 single cells. Orthothecium hyalopiliferum is presently known only from the Chinese provinces of Guizhou, Sichuan, and Yunnan.

Leioderma cherokeense P. M. Jørg. & Tønsberg sp. nov. is described from North Carolina, U.S.A., where it grows on bases of trunks of Liriodendron tulipifera. Apothecia and structures for vegetative dispersal are not known. The genus Leioderma is new to eastern North America.

The genus Splachnum is newly recorded from Brazil based on a collection from Santa Catarina. Inferences from two chloroplast loci, the trnL-trnF region and the rps4 gene, indicate that this sample is closely allied to the primarily North American S. pensylvanicum, but differs by several mutations. Examination of populations of S. pensylvanicum suggests that this species is fairly variable morphologically, and that the Brazilian specimen, although atypic, cannot be distinguished from the Northern Hemisphere populations. The population from Santa Catarina, Brazil, is only the second record of this species from South America and the first from the Southern Hemisphere.

The sporophyte structure of Cavicularia densa Steph. was investigated and described in detail with photomicrographs. Taxonomic and phylogenetic discussions, based on the sporophyte features, are made on the genus Cavicularia, as well as on the genus Blasia. Characters newly noted include the bulbous foot, a rudimentary collar at the base of capsule, semiannular or helical thickenings of the inner capsule wall, several layers of transfer cells on both sides of the placenta, and the presence of a single large plastid in the early stage of the sporocytes. The occurrence of monoplastidic sporocytes in both Cavicularia and Blasia strongly support their inclusion is the family Blasiaceae in the metzgerioid liverworts.

The mountain caribou is a threatened ecotype of the woodland caribou restricted to east-central and southeast British Columbia as well as adjacent portions of Washington and Idaho. In winter these animals forage almost exclusively on arboreal hair lichens, especially Bryoria. Here we examine the vertical and horizontal occurrence of hair lichens within the canopy of a mid-successional, mid-elevational forest dominated by Engelmann spruce and subalpine fir. Our study yielded five key findings: 1) all hair lichen species potentially important to caribou are present 60 yr after stand initiation; 2) low-biomass sorediate species (mostly B. fuscescens) predominate in the lower and middle canopies; 3) high-biomass non-sorediate species (mostly B. fremontii and B. pseudofuscescens) are most abundant in the upper canopy; 4) hair lichen biomass is higher in open stands than in closed stands; and 5) hair lichen loadings are low when compared with earlier reports from old-growth stands. The last finding apparently reflects—in the upper canopy—a lack of defoliated branches and—in the middle and lower canopies—humid, poorly ventilated conditions. We suggest that a judicial use of stand thinning could considerably augment the production of non-sorediate Bryoria species in defoliated portions of the middle canopy. Within the lower canopy, however, thinning is unlikely to increase Bryoria loadings, except as a result of inoculation from the middle canopy.

Sun and shade samples of two aquatic bryophytes, the moss Fontinalis antipyretica and the liverwort Jungermannia exsertifolia subsp. cordifolia, were collected from a mountain stream and cultivated in the laboratory under two artificially imposed radiation regimes: control (only photosynthetically active radiation, PAR) and UV-B (PAR UV-B). Samples were cultured at 2°C for 78 hr under continuous radiation to determine whether the physiological responses of the two bryophytes to UV-B radiation depended on their previous field acclimation to sun or shade conditions. We also aimed to study whether the short-term effects of UV-B were similar to those caused by longer exposure. Fontinalis antipyretica was more sensitive to UV-B treatment than Jungermannia exsertifolia subsp. cordifolia, showing significant decreases in several physiological variables indicative of vitality: P_N rates, OD₄₃₀/OD₄₁₀, OD₆₆₅/OD_665a and especially F_v/ F_m. This higher sensitivity occurred in both sun and shade samples of the moss. These results reproduce the differences between both species that were found in previous more prolonged (36– 82 days) experiments. These types of short-term tests may therefore be used instead of long-duration tests to evaluate the UV-B tolerance of bryophytes. Shade samples were more sensitive to UV-B treatment than sun samples, but only in the more UV-B-sensitive species (Fontinalis antipyretica). F_v/F_m was the physiological variable that better discriminated both types of samples in the moss, since it decreased 42% in the shade samples and only 27% in the sun samples at the end of the culture period. In Jungermannia exsertifolia subsp. cordifolia, controls and UV-B-treated samples were not significantly different in either the sun or the shade samples. Principal Components Analyses (PCA) for each species, ranking the physiological results along the culture period for each radiation regime and field exposure strongly supported these conclusions and also showed that the loading factors of PCAs may be helpful for establishing the combination of key variables responsible for the differences between controls and UV-B-treated samples, or between UV-B-treated sun and shade samples.

Imbribryum was previously accidentally invalidly published and is validly published here.