Pseudocyphellaria perpetua McCune & Miadlikowska is described as a new species of lichenized fungus from Oregon, U.S.A. Morphologically similar to some forms of P. crocata, P. perpetua is separated from that species by a yellow medulla and predominantly marginal soralia. Comparison of ITS and LSU nrDNA sequences support taxonomic distinctness of these two species. Phylogenetic analyses were conducted on LSU and ITS nrDNA data sets separately and simultaneously using maximum parsimony and maximum likelihood as optimization criteria. All analyses except one (maximum parsimony on LSU nrDNA data alone) confirmed the monophyly of P. perpetua. There are two distinct groups within the P. perpetua clade represented by specimens sampled from near the type locality in Oregon, and specimens outside of Oregon (eastern Canada, eastern Russia and eastern U.S.A.). The genus Pseudocyphellaria is very likely polyphyletic, consisting of at least two highly divergent groups.

The difference in species diversity on different substrates and the effect of both substrate (ground, logs, rocks, trees, and fallen branches) and site variation (such as disturbance history, aspect, slope) on bryophyte and lichen diversity were investigated in eastern Australian forests. Thirty-five sites in forest types ranging from dry sclerophyll to riparian were surveyed using a 50 m × 20 m area. Despite strong differences between the different substrates in species richness and composition for both bryophytes and lichens, differences within each substrate were limited. On examining each substrate separately, we found that variation in substrate quality, such as degree of log decay, was not strongly correlated with species diversity, explaining no more than 16% of richness and 5% of composition. Despite both bryophytes and lichens showing high fidelity for particular substrates, the quality of that substrate was not an important factor in determining species diversity in this study. Site environmental variables explained larger variation in both bryophyte and lichen species diversity, in particular species richness, with individual site variables explaining up to 41% of richness (topographic position) and 6% of composition (time since fire). For some site variables, notably some of the disturbance variables, there were no overall trends, but significant results for particular substrates, such as logging being significant only on logs and trees.

We here report 359 species in 103 genera from Yellowstone National Park. We found 71.3% of the total number of species in Picea engelmannii forests and 57.4% of the total number in Pseudotsuga menziesii stands. This compares to 42.3% of the species in Pinus contorta and 37.0% of the species in Pinus contorta/Pinus albicaulis stands. The presence of old Pseudotsuga menziesii and mature Picea engelmannii indicates that the forests have not burned for at least 300 yr, contributing to higher lichen diversity. The drier lodgepole pine and whitebark pine forests burn more frequently than every 300 yr and have fewer microhabitats for lichen growth. Species with thalli large enough to identify are beginning to recolonize substrates burned in the 1988 fires. Bryoria fremontii and Letharia vulpina exhibit levels of mercury and sulfur higher than those in other specimens in the region.

Fissidens hyalinus Hook. & Wils. is often considered to be one of the rarest mosses in the United States. The species, however, is much more common than has previously been assumed. Sixty-five new collections of F. hyalinus, in combination with previous collections, document the species from 28 counties, 7 states, and 5 major physiographic provinces. The species is newly reported for Alabama, Tennessee, and Virginia. Fissidens hyalinus is most frequent on bare soil of streambanks in steep and deeply dissected landscapes with calcareous geology and mixed deciduous forests.

This study has shown a clear edge effect on the green-algal lichen community on spruce branches in a middle boreal spruce forest. Measurements of the following parameters from lower tree branches were carried out at five transects parallel to the SE facing forest edge: species richness, lichen cover, proportion of morphologically aberrant thalli, and size distribution of Platismatia glauca, and length and number of pendulous thalli. The transects were located at 0, 8, 16, 32, and 64 m´s distance from the edge. The intensity of edge effects are found to be species-specific as some species showed pronounced edge response e.g., Cavernularia hultenii, Hypogymnia tubulosa, and Platismatia glauca. In general, the lichen pioneer community distributed on the outermost part of the spruce branches are most affected by the edge environment. A low frequency of small thalli of P. glauca and Bryoria spp. at the edge, compared to forest interior, may indicate unsuccessful colonization, depressed growth, or low supply of diaspores at the edge. Wind and snow abrasion at the edge are probably important factors explaining the observed lichen response.

We revised the original material of the invalidly published names Pyrenotrichum ‘atrocyaneum’, P. ‘mirum’, and P. ‘podosphaera’ R. Sant. Pyrenotrichum ‘atrocyaneum’ represents the campylidia of the recently described Kantvilasia hians, while P. ‘mirum’ corresponds to the campylidia of ‘Lopadium’ tayabasense, a species that externally resembles Calopadia, but differs in the ellipsoid, non-septate conidia and the richly branched and anastomosing paraphyses. The new genus Calopadiopsis is established to accomodate this taxon. Pyrenotrichum ‘podosphaera’ represents a genuine Sporopodium, externally resembling the pantropical, well known S. phyllocharis and S. xantholeucum, but featuring unique, 1-septate conidia. This taxon is here formally introduced as a new species, S. podosphaera. Diagnostic features of all lecanoralean taxa producing campylidia are summarized.

Lecidea ramulicola (= Lecanora symmicta f. ramulicola) is raised to species rank within Lecanora. It is anatomically similar to Lecanora symmicta, but unlike that species it has atranorin as major secondary product and usnic acid only as an accessory substance, more frequently branched and anastomosing paraphyses, and shorter conidia. The species is known from northeastern North America and central Europe, where it is often found in pine forests, most frequently on dead pine twigs.

Two squamulose species and one crustose species of Trapeliopsis are described from the western United States based on morphological, anatomical, and ITS sequence data. The newly described species pair, T. californica and T. steppica, consistently differs from T. wallrothii in morphology, ascospores, secondary products, and ITS sequence. Previous reports of Trapeliopsis wallrothii from North America should be referred to T. californica. Morphologically similar to Trapeliopsis californica, T. steppica is separated from that species by the presence of dark granular soredia in discrete roundish soralia; a thinner, duller cortex; and slightly smaller and more appressed squamules. Trapeliopsis steppica is apparently endemic to western North America, predominantly in the intermountain region. Trapeliopsis californica, an esorediate frequently fertile species, predominates in California and west of the Cascade crest in the Pacific Northwest. The third new species, T. bisorediata, is a rarely collected, but locally common in the semi-arid intermountain region of the Pacific Northwest. It is characterized by soredia of two types on a whitish pruinose crustose-areolate non-lobate thallus.

The effects of four increasing levels of KH₂PO₄ on the physiology of the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia were analyzed in the laboratory in the short term (15 d). The accumulation of P and K in the liverwort tissues was influenced (ANOVA) by the level of KH₂PO₄-enrichment and was significantly higher in the more enriched culture solutions. However, only the concentration of P was influenced by the effect of time (ANOVA), and the gradual P accumulation throughout the culture period contrasted with the fluctuations observed in K accumulation; these were presumably due to the higher liability of K to be leaked from the cells. Our results suggest that the analysis of P in transplants of J. cordifolia may be a useful bioindicator of short term water eutrophication both in the spatial and the temporal scales, although the highest PO₄³⁻ concentration used in this study (20 mg liter⁻¹) may induce a P saturation in J. cordifolia tissue (0.53% DM). The rates of net photosynthesis showed a significant quadratic regression with the tissue P concentration, which might resemble the action curve of mineral nutrients. Using this regression as an indicator, there was no clear deficiency zone, probably due to the relatively high tissue P concentration initially found in the liverwort. The lack of stimulation of net photosynthesis with increasing tissue P could be due either to a deficiency in other mineral elements such as N, or to an intrinsic inability to use the excess of nutrients. The decline in net photosynthesis when the tissue P concentration exceeded 0.45% DM could be interpreted as a toxicity process. Chlorophyll concentration was not affected by P enrichment, but the decline in the chlorophyll a/b ratio and in the proportions of chlorophylls to phaeopigments, together with the increase in the proportion of carotenoids to chlorophylls, suggested also P toxicity. This phenomenon needs further investigation to be confirmed in other species and conditions, but it may help to explain the disappearance of certain aquatic bryophytes in eutrophicated water courses. The physiological effects of increasing tissue K concentration (decreases in the rate of dark respiration and in the chlorophyll a/b ratio) were slighter than those of P, probably because the accumulation of K was lower than that of P (1.44 and 1.96 times the initial value, respectively). In a different experiment in which J. cordifolia was cultured in P-enriched aerated and non-aerated solutions, anoxia caused a strongly diminished P accumulation in the first three days, probably because the mitochondrial respiration was blocked. Then, a clear net loss of P from the liverwort tissues was observed, maybe caused by membrane damage.

When abandoned peatlands undergo restoration following the extraction of peat moss, newly reintroduced diaspores may be buried by particles eroded from the stripped peat (decomposed) or from adjacent extraction activities. This study examined, in the greenhouse, the tolerance of six species of peat mosses to burial by peat. One of the experiments consisted of depositing predetermined thicknesses (0, 10, and 30 mm) of peat onto partially established mats of Sphagnum species and true mosses. A second experiment evaluated the effect of a wider range of burial depths (maximum set at 40 mm) on Sphagnum fuscum. After ten weeks of burial, the expansion of the established mosses buried under 10 mm of peat was slowed down but not arrested. Dicranella cerviculata is the only species that did not tolerate being buried. The mosses showed three types of final responses to burial: neutral, in which the increases and decreases in cover were not significantly different between the tested and the control depths (for Sphagnum fuscum buried under 5 mm and Sphagnum fallax buried under 10 mm); negative, in which the decrease in cover was significant at the depth tested (for Sphagnum fuscum, Sphagnum magellanicum, Polytrichum strictum, and Dicranella cerviculata buried under 10 mm or more, and for Sphagnum fallax and Sphagnum capillifolium buried under 30 mm of peat); and positive, in which the increase in cover was significant at the depth tested (for Sphagnum capillifolium buried under 10 mm of peat). After burial, mosses emerged by means of an innovation or a continuity of the stem of the initial individual for the Sphagnum species, and by means of an innovation growing out of the apex of buried individuals in the case of Polytrichum strictum. It appears that restoration efforts may be futile in cases where diaspores and newly established mats are likely to be buried at depths exceeding 10 mm.

Parmelia sulcata Taylor is generally believed to be fairly pollution tolerant, and consequently it is sometimes collected in urban and/or polluted localities. The condition of these specimens, however, is not always luxuriant and healthy. This study tested the hypothesis that total thallus and algal layer thickness, and the algal layer ratio would be thinner in polluted areas, thus allowing these characters to be used a indicators of air pollutant effects. Herbarium specimens were studied from 16 different localities varying in pollution level. The thallus and algal layers and ratio were not affected by year or locality of sampling, but decreased 11, 31 and 21% respectively between low and high pollution level localities. These results agreed with earlier studies using other species, but further work is needed to clarify the effects of geography and substrate on these phenomena.

One hundred eighty-eight taxa of lichens are reported from Simeonof Island in the Shumagin Islands of southwestern Alaska. Wide-ranging arctic-alpine and boreal species dominate the lichens; a coastal element is moderately represented, while amphi-Beringian species form a minor element. The lichen component of Empetrum nigrum dwarf shrub heath, the dominant vegetation type, was analyzed to identify the most frequently occurring lichens within this community.

Biatora printzenii sp. nov. is described from eastern North America. Cheiromycina flabelliformis, Chrysothrix chrysophthalma, Opegrapha corticola, and Rinodina flavosoralifera are reported new to North America. The report in The Bryologist 99: 196 (1996) of Fuscidea lightfootii as new to North America was based on misidentifications.

On Easter Island (Chile) 11 species of liverworts and a single hornwort species are recorded, mainly based on a recent collection by Robert R. Ireland & Gilda Bellolio. Among them, Marsupidium knightii Mitt. and Jackiella javanica Schiffn., are new to the New World. The latter is likewise the first New World record of the genus Jackiella Schiffn..

The Bryum bicolor complex includes four species in North America: B. bicolor, B. gemmilucens, B. gemmiferum, and B. barnesii. Bulbil morphology is the most important taxonomic character for delineating the four North American species recognized, but care must be taken not to confuse them with morphologically similar restricted buds produced by other Bryum species. Bryum bicolor is the only northern hemisphere species of the complex with bulbils single per leaf axil, but is sometimes considered to be identical with the southern hemisphere species, B. dichotomum. After examination of the North American herbarium material and the types of B. bicolor and B. dichotomum, we could not perceive morphological differences between the two species. However, our survey did not include any other southern hemisphere specimens and we therefore kept the name B. bicolor pending for further studies on the variability of the species of the complex in the southern hemisphere. Bryum barnesii, B. gemmiferum, and B. gemmilucens all produce many bulbils per leaf axil but differ in bulbil color, shape. and size. Bryum gemmilucens is characterized by 100–200 μm long yellow, orange or red bulbils; B. barnesii by usually larger, 200–450 μm long greenish bulbils with broad, obtuse to largely acute primordia; and B. gemmiferum by 150–350 (450) μm long, yellow green, rarely brownish bulbils with tooth-like primordia. Leaf morphology is too variable to be used as a reliable taxonomic character within the complex. Costa length is quite variable, and plants exhibiting large bulbils and strongly excurrent costa approach B. dunense, considered to be a synonym of B. bicolor. Similarily, plants with broad leaves and laminal cells approach B. balticum, considered to be conspecific with B. barnesii. Bryum bicolor has been reported from 25 states of the United States and six Canadian provinces. Bryum barnesii, newly reported from North America, is most common along the Pacific coast, whereas both B. gemmiferum and B. gemmilucens are considered rare in North America.