This paper treats four North American yellow or orange sorediate species, C. chrysodeta, C. citrina, C. tominii, and C. xanthostigmoidea. These species are mostly sterile and sorediate and usually occur on rocks and soil. Other related non-American species, C. proteus, C. soropelta, and C. xantholyta are also discussed in relation to the treated species. Descriptions, distribution maps, and color illustrations are provided for the treated taxa.

Three lichen species forming both a foliose chlorotype and a dendriscocauloid cyanotype are documented from western North America. Lobaria amplissima is reported from northern California and southeastern Alaska and is new to North America. Sticta oroborealis Goward & Tønsberg, sp. nov. is described from a small area in north coastal British Columbia. The cyanotype of Sticta wrightii, hitherto unknown, is reported from coastal southeastern Alaska. The cyanotypes of all these species occur primarily as epiphytes in old-growth forests supporting a high cyanolichen diversity. The occurrence of “Dendriscocaulon” intricatulum (Nyl.) Henssen in Pacific North America is questioned.

Using field emission scanning electronmicroscopy, hyphal surfaces were examined in six lichens, Lasallia papulosa (Ach.) Llano, Xanthoria elegans (Link.) Th. Fr., Peltigera aphthosa (L.) Willd., Stereocaulon depressum (Frey) M. Lamb, Umbilicaria mammulata (Ach.) Tuck, and U. cylindrica (L.) Duby and in material of the same species associated with pathogenic or saprobic fungi. In samples infected by each of Muellerella pygmaea (Körber) D. Hawks., Marchandiomyces corallinus (Roberge) Diederich & D. Hawks., Lasiospheriopsis stereocaulicola (Lindsay) O. Eriksson & R. Sant, and a Penicillium-like fungus, some hyphae were found that differed from those of the lichen mycobiont in size, septation, surface texture, or inclination to collapse. Anomalous hyphae were uncommon in some diseased lichens, in fact no candidate pathogens were detected in S. depressum infected with Arthonia stereocaulina (Ohlert) R. Sant., although extensive mycelia of L. stereocaulicola were evident in the same lichen. The extent of visible colonization by extraneous fungi was greatest in recently killed U. mammulata.

One hundred thirty-nine taxa of lichens including two lichen parasites are reported from St. Matthew and St. Paul Islands in the Bering Sea. Caloplaca lithophila is new to 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. In comparison with St. Paul Island, St. Matthew Island is richer in arctic-alpine species.

Substrate specificity has been pinpointed as key to understanding plant species distributions and to differentiating types of plant rarity. Substrate specific distribution patterns (e.g., calcicole and calcifuge) are particularly prevalent among bryophytes. Many authors have suggested that the effects of substrate chemistry might be most important during the establishment stage. The connection between substrate sensitivity during establishment and the degree of substrate specificity (i.e., substrate breadth) measured for adult plants in the field was explored for three rare moss species, Mielichhoferia macrocarpa, Didymodon johansenii, and Mnium arizonicum and three taxonomically allied common species, Bryum pseudotriquetrum, Didymodon rigidulus var. gracilis, and Mnium spinulosum, respectively. Substrate pH and organic matter content were determined for field samples to quantify species substrate breadths. These observed specificities were tested by comparing regeneration of gametophyte fragments on native and chemically opposite, non-native substrates. The three rare species were not consistently more substrate specific than their paired common species. Overall, establishment was higher on native substrates. The two moss species, M. macrocarpa and D. rigidulus var. gracilis, with the narrowest substrate breadths for pH and percent organic matter, were also the most sensitive to regeneration on non-native substrate. The significantly higher sensitivity of these two calcicole species in comparison with the other study species demonstrated that these calcicole species were more immediately sensitive to regeneration on non-native substrates than the calcifuge species, M. arizonicum and M. spinulosum and the calcicole species found on substrates with a wider range of organic content, B. pseudotriquetrum and D. johansenii, were less sensitive to substrate chemistry during regeneration. The use of regeneration experiments for exploring the degree and basis of species habitat specificities can help to resolve which habitat parameters physiologically limit the species. Information gained from such studies could be particularly useful for managing rare bryophyte populations.

The sexually dimorphic liverwort, Sphaerocarpos texanus, can be used to study changes in sex ratios in a cohort of individuals during different life stages, from spore development to germination to senescence. Recent attempts to germinate spores under controlled conditions have been successful. This study used laboratory-derived spores to detect subtle sex-specific differences in germination in a cohort of spores across different dormancy breaking temperatures. Sex ratios were determined for subsets of sporelings held at 35/20, 30/15, and 25/15°C for one to eight wk. Sex ratios were female biased for spores that lost dormancy in the 25/15°C and when the data were pooled across the three dormancy breaking thermoperiods. This pattern coupled with the potential for spore banks formation in S. texanus can lead to a single cohort of spores influencing the sporeling sex ratios across seasons.

The frequencies of states of 86 characters in 439 pleurocarpous moss species from all over the world are compared across climatic zones, general habitats, and the gradient wetland versus non-wetland. Forty-four percent of the characters are influenced by climatic zone, 35% by general habitat, and 23% by the wetland vs. non-wetland gradient. Most of the differences in character state frequencies among environmental categories seem to relate to two complex functions: 1) water conduction and retention, as expressed by differences in frequencies of states of the characters stem central strand, leaf orientation, leaf costa type, alar cells, paraphyllia, pseudoparaphyllia, inner perichaetial leaf plications, vaginular paraphyses, operculum type, stomatal pore, and possibly seta length and 2) spore dispersal, expressed by variation in frequencies of character states related to capsule shape and orientation, annulus, exostome and endostome appearance, spore size and maturation time, and possibly seta length. Besides the influence of the phylogenetic history, water availability and exposure to wind are suggested to be the most important habitat factors explaining the differences among habitats found for these character complexes.

The past two decades have seen rapid advances in diaspore (in particular seed) bank research, and conceptual and technological advances promise more in the near future. Studies on bryophytes may contribute significantly by helping to assess the scope of generalizations of seed bank studies, but bryophytes may also provide interesting perspectives of their own, due to their peculiar life history—e.g., consequences of self-fertilization in monoecious species and often complex life histories.

Plants of Pseudoscleropodium purum, a moss native to central and western Europe, are well established in western, central, and eastern New York State, mainly in lawns of cemeteries, especially those with moist clayey soil, shade provided by conifers (Picea abies, Thuja occidentalis) in small groves, and periodic mowing. Male and female plants occur in Rensselaer County, New York cemeteries, but not in the same ones. Sporophytes have not been found, and reproduction appears to occur vegetatively as plants are cut and spread during lawn maintenance. If spore production is established within the naturalized range of this moss in the northeastern United States, the species may become more widespread, and possibly invasive. While the date and method of introduction into the State of New York are unknown, a 19th century specimen of P. purum from the West Coast of North America indicates that the moss may have reached that region as packing material in the late-1800's.

A re-examination of populations of Aloina bifrons from the Mojave Desert of Nevada was prompted by observations of frequent sporophytic populations. Sporophytic populations are unusual for xeric dioicous species. Aloina bifrons, previously described as dioicous, was found to be occasionally rhizoautoicous. Ramets bearing perichaetia and ramets bearing perigonia were at times connected beneath the ground surface by single rhizoids, rhizoid strands, or by masses of rhizoids. Rhizoautoicy probably functions in increasing spore production in environments unconducive to fertilization.

The new species, Schaereria porpidioides, is described from collections made by H. A. Imshaug & R. C. Harris from the Falkland Islands in 1968. The systematic position of Schaereria, with respect to its relationship to Trapelia, is discussed.

Widespread abortion of sporophytes in the desert moss Grimmia orbicularis occurred following unusually heavy summer rainstorms in the Mojave Desert of southern Nevada. Approximately 50% of the sporophyte cohort aborted, the majority in the seta elongation phenophase. Just prior to the abortions, an August rain event equivalent to one-half of the normal annual precipitation occurred over a period of less than six hours. Abortive sporophytes were significantly shorter and had significantly less biomass than viable mature sporophytes from the same cohort. A phenological and length analysis of the sporophyte cohort indicates that the sporophyte abortions occurred over a very brief period of time. It is postulated that the stresses brought on by desiccation/rehydration cycles during the summer heat in the desert, in conjunction with the presence of an abnormally advanced phenophase (early seta elongation), may have resulted in an inability to either repair the cellular damage or resulted in insufficient nutrients for sporophyte maturation.

Three species of Saccogynidium Grolle (Geocalycaceae, Hepaticae) are recognized in China. Saccogynidium rigidulum (Nees) Grolle and S. muricellum (De Not.) Grolle are confirmed from Taiwan, and S. irregularospinum Gao, Cao, & Lai from Tibet and Taiwan is described as new to science. A key to Chinese species of Saccogynidium and illustrations of each species are presented.

Gyalideopsis floridae, a lichenicolous lichen growing on Parmotrema in Florida (U.S.A.) is described as new. It is distinguished from all hitherto known species of the genus by multispored asci and simple ascospores.

Using spectral filters, Cladonia uncialis and Cladina rangiferina were exposed for seven days to visible light supplemented with two intensities of three different bands of ultraviolet in a growth chamber. The concentrations of lichen secondary products separated by thin-layer chromatography were then determined densitometrically. In Cladonia uncialis, higher intensity exposure to visible light enhanced with UV-A, while UV-B and UV-C were excluded, significantly increased usnic acid concentrations over control levels. However, less usnic acid accumulated under high intensity enhancement of both UV-A and UV-B. The effect of supplemental UV-A and UV-B was the same on atranorin concentrations in Cladina rangiferina. This suggested that UV-A caused increased accumulation of both compounds, but that the effect was negated by UV-B. Concentrations of usnic acid in natural populations of Cladina mitis were significantly lower in spring and summer when UV-B flux is greatest.

Cyathodium bischlerianum is described as a new Neotropical species from Panama. The species is distinguished by its slender, delicate thallus; a prominent dorsal pore at base of involucre; monoicous condition with 1–2 archegonia per involucre, and male receptacles on sides of thallus; sporophytes without operculum; cells of upper third of capsule with bar-like thickenings; elaters attached to base of capsule wall with 3–4 bands; and spinose-bulbose spores. This species resembles the Asiatic C. aureonitens in spore ornamentation, but its monoicous condition, lack of operculum, naked involucre, and ornamentation of upper capsule cells separate it from its Asiatic relative. It is also related in morphology, sexual condition, and spore ornamentation to C. cavernarum.

Hypogymnia arcuata and H. sachalinensis are described as new species of lichenized fungi from east Asia (Russia, China, and Japan). Closely related to H. fragillima, H. arcuata is separated from that species by the less frequently confluent holes in the lower surface, more broadly divergent branching, and the presence of 2′-o-methylphysodic and 3-hydroxyphysodic acids by TLC. Formerly confused with the North American endemic H. duplicata, H. arcuata lacks the long, cascading lobes and physodalic and protocetraric acids of H. duplicata. Hypogymnia sachalinensis has long been confused with the North American endemic H. enteromorpha under the name H. enteromorpha var. inactiva. Hypogymnia sachalinensis is smaller than H. enteromorpha, with appressed to imbricate, narrower lobes. Hypogymnia enteromorpha is unknown from Asia.

The South African hepatic, Lepidozia succulenta Sim, currently placed in Telaranea, is a Paracromastigum of the Bonneria-group, characterized by both Frullania- and Acromastigum-type terminal branching, succubous leaves, the insertion of which does not extend to the stem midline, and the dorsal cortical cells broadly exposed.