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Old conifer forests in the Pacific Northwest have a wide range of microhabitats induced by canopy structure and substrate characteristics. We used the Wind River Canopy Crane to sample lichens and bryophytes throughout the spectrum of habitats available to epiphytes. Of the 111 species found in 72 sample units, 97 were lichens and 14 were bryophytes. Epiphyte communities showed marked variation with respect to height in the canopy, bark vs. wood, degree of sheltering, and stem diameter. Of these factors, height in the canopy was most strongly related to epiphyte communities. Furthermore, the top two meters of the tallest trees hosted a diverse assemblage of both rare species (Tholurna dissimilis) and weedy, nitrophilous species (Candelaria concolor, Hypogymnia tubulosa, Parmelia sulcata), presumably induced by birds delivering lichen propagules and nutrients. Ten species were more frequent on bare wood than bark, including Ophioparma rubricosa, Letharia vulpina, Placynthiella spp., Ptychographa xylographoides, Trapeliopsis flexuosa, and Xylographa parallela. Species richness was highly variable, even within habitats. The only factor found related to species richness was height in the canopy, the middle and upper layers each having about twice the species per sample unit as lower in the canopy.
We document the effect of Mexico City on the epiphytic lichens of Abies religiosa by comparing the communities occurring at Desierto de los Leones, a protected area near to the city, with those at El Chico National Park, a location 100 km upwind (or crosswind) from the city. The first community had 47% fewer species, 62% less lichen cover, and a species abundance pattern that revealed a highly disturbed community. The differences between these communities were greater at the trunk base than at the height of two m, and much stronger when evaluated from a species to species perspective. Among a variety of factors, site air quality may account for many of the observed differences.
Air quality studies often take advantage of the ability of lichens and mosses to accumulate certain contaminants in their tissues. In order to evaluate the rate of contaminant accumulation from concentrations in tissues, the age of the tissue must be known. Our objective was to develop and test a method for estimating annual growth rates and thallus ages for Masonhalea richardsonii, a vagrant clonal lichen abundant throughout its Beringean range. The annual growth rate of healthy individuals from Arctic Alaska, based on the 75th percentile of a cumulative frequency distribution, was 11.6% (90% confidence interval: 11.2–13.3%). This growth rate suggests that the biomass of a healthy M. richardsonii individual doubles within a period of approximately 6.3 years (90% confidence interval: 5.6–6.5 years). Average ages for the thalli in this study were estimated at 5 to 41 years using a negative compound interest formula and assuming initial masses of thallus fragments. Calculations and their appropriate application are shown and the methodology is discussed.
The patterns of cover and species diversity (richness and composition) of macro-lichens, bryophytes, and vascular plants are described for a Canadian montane forest in an area where the forest is highly valued both for wood production and for the terrestrial lichen that is a vital part of the diet of the endangered woodland caribou (Rangifer tarandus caribou Gmelin). In 180, 6.5 m × 6.5 m plots placed in nine stands within a 375 km2area, we found lichens were abundant, but the ground layer was dominated by feather moss. Mean species richness at the plot level for lichens (23) is about double that of bryophytes (13) and vascular plants (11). Differences in species composition are small with any two plots having in common at least 50% of their vascular plants, 60% of their bryophytes, and 70% of their lichens. Comparisons of 10% of the most open with 10% of the most dense canopy plots revealed that the more open sites have greater lichen cover, higher elevation, older trees, more lichen and vascular plant species, less moderately decayed logs, and lower cover of Pleurozium schreberi, the dominant feather moss. Twenty-two species (14%) were found only once; of these five were lichens (9% of the lichen flora), six bryophytes (17% of the bryophyte flora), and 11 vascular plants (17% of the vascular plant flora). None of these is provincially endangered, but all are rare in this particular forest type. Only three of these species occur in the 20% of sites having the most open or dense canopies. Our data indicate that at the local scale, the ground layers of these forests are highly variable and have little local distinctiveness. The lack of strong environmental correlations with species patterns suggests that within the natural forest regime other factors are at least partially responsible for ground layer patterns at the local scale. These may include dispersal and establishment success as well as stochastic disturbance regimes.
We have studied the sporophyte-gametophyte junction at the post-meiotic stage in five pleurocarpous mosses: Isothecium myosuroides Brid., Leucodon canariensis (Brid.) Schwaegr., Leptodon longisetus Mont., Neckera cephalonica Jur. & Unger, and Neckera intermedia Brid. In all five species the foot does not penetrates the leafy caulidium. The junction in all of them corresponds to a “bryalean pattern”, with transfer cells both in the gametophyte and sporophyte. However, except in Neckera intermedia, there were several layers of foot transfer cells, deviating from the typical 1:1 arrangement in this model. At this stage, the tissues of both foot and vaginula were degenerating. Vaginular cells surrounding the foot became empty and thin-walled. Opportunistic microorganisms were often found. The five species differ with respect to the number of layers of transfer cells and the degree of development of foot hydroids.
This is a preliminary study of a group of North American taxa of Lecanora occurring on bark and containing usnic or isousnic acid and having a yellow, yellow-green, or greenish thalli. The group is regarded as L. varia s. lato and, based on species examined, a proposal is offered to delimit the following smaller groups: L. varia group s.str.; L. expallens group s. lato with L. strobilina and L. expallens group s.str.; and the L. saligna group. Two new subspecies (L. varia subsp. densa and L. varia subsp. laxa) are described. A key for the taxa studied is presented. Some suggestions for future research are outlined.
The terricolous lichen Peltigera chionophila sp. nov. is described from the western cordillera of North America. It can be distinguished from other members of the P. aphthosa group by its even lobe margins, its uniformly corticate apothecial reverses, its well-defined veins that darken gradually toward the thallus centre, and by its strict occurrence in mountainous regions subject to heavy, prolonged snow cover. Comparisons of sequences of the Internal Transcriber Spacer of the nuclear ribosomal DNA repeat support the taxonomic distinctness of this species. A map of its global distribution is provided.
A new species, Cheilolejeunea gaoi (Hepaticae, Lejeuneaceae) from Guangxi, China, is described and illustrated. It differs from other Cheilolejeunea species in its marginal denticulation of the leaf lobe and of underleaves. These are formed by projecting corners of two adjacent cells rather than single projecting cells. The new species resembles the genus Pictolejeunea in plant habit, leaf cells, perianth shape, absence of gynoecial innovation, and structure of apex of leaf lobule. However, the former differs primarily in the marginal position of the hyaline papilla of the leaf lobule and the absence of ocelli in the leaf lobes and underleaves.
The genus Bryochenea is evaluated by a study of morphological characters from type and other herbarium specimens. The type species, B. ciliata, is taxonomically synonymous with Cyrto-hypnum vestitissimum; therefore, Bryochenea is synonymous with Cyrto-hypnum. Bryochenea sachalinensis, the only other species, has been treated as Helodium sachalinense by most authors. An evaluation of the generic and familial positions of B. sachalinensis, based on comparisons with Helodium and 12 other hypnalean genera, indicates that B. sachalinensis is sufficiently distinct to warrant generic rank. A monotypic genus, Echinophyllum, is described and the new combination, E. sachalinensis, is made. The combination of dry branch leaves that are catenulate, short and strongly unipapillose leaf cells, and lanceolate pseudoparaphyllia with laciniate margins and papillose basal cells support inclusion of Echinophyllum in the Thuidiaceae; however, the elongate paraphyllial cells and elongate apical cells of branch leaves are incongruent with Thuidiaceae and instead suggest closer affinity to Helodiaceae, Hylocomiaceae, or Leskeaceae. The closest match among these alternatives is with Helodiaceae, but there are sufficient differences in habitat, leaf areolation, and pseudoparaphyllia that the alignment with Thuidiaceae is considered preferable.
The concentrations of seven elements (N, P, K, Ca, Mg, Fe, and Na), five of which are macroelements, were measured in 3-cm apices of 17 populations of the euryecious aquatic moss Rhynchostegium riparioides (Hedw.) Card. located along the course of the Iregua River (La Rioja, northern Spain). A principal components analysis (PCA) revealed two key factors ordinating the sampling sites on the basis of their physicochemical data 1) substrate lithology, since the river's upper course is predominantly siliceous whereas the middle and lower courses are influenced by CaCO3and 2) human impact, especially observed in the irrigation channels of the lower course. The element concentrations in the tissues of R. riparioides, generally comparable to those cited for other aquatic bryophytes, were strongly and significantly correlated with the respective element concentrations in the surrounding water. Therefore, the PCA ordinating the moss populations on the basis of their element concentrations was highly coincident with the physicochemical PCA: the headwater populations had the lowest element concentrations, the middle course populations were notably Ca-enriched, and the lower course populations showed the highest concentrations of N, P, K and Na. The significant correlations between the element concentrations differentiated two groups of elements: mainly intracellular ones (N, P, and K), and mainly exchangeable ones (Ca and Mg). This dichotomy was also noticed in other respects 1) the relationship between the water and the tissue element concentrations was linear for N, P, and K, but similar to a Michaelis-Menten saturation-type curve in the case of Ca and Mg; 2) the quotients between the concentration of a given element in moss and in water (enrichment ratios, ER) were much higher for N, P, and K than for Ca and Mg; 3) only the tissue concentrations of Ca and Mg were correlated–negatively–with their respective ERs. Na showed somewhat peculiar characteristics, probably reflecting weak uptake efficiency and metabolic irrelevancy. ERs were strongly dependent on the respective element concentrations in water through hyperbolic relationships, suggesting that the uptake efficiency may be higher when elements are more diluted in water and decreases as the moss becomes saturated. This plasticity, to be expected in such an euryecious species as R. riparioides, would permit the acclimation of the different populations to changing water chemical conditions in order to avoid nutrient deficiencies.
Constant extreme leaf dimorphism in the moss family Calymperaceae, involving evolution of the gemmiferous leaf of some species into a rod-like essentially naked costa or a narrow tube-like or channeled shaft, occurs more or less consistently in five species of Calymperes and six species of Syrrhopodon world wide (approximately eight percent of the species of the family), but not in the closely related genus Mitthyridium. Such highly derived gemmiferous leaves—referred to here as stenophylls—are an evolutionary phenomenon that is not known for any other group of mosses. The stenophylls bear the gemmae on their tips, are rigidly erect both wet and dry, are generally longer than and mostly have smaller areas of cancellinae than the vegetative leaves. The principal functional-evolutionary benefit of this type of extreme leaf dimorphism may be the constant (plants hydrated or desiccated) presentation of the gemmae for dispersion elevated above the potentially trapping tangle of vegetative leaves of the moss turf. Also, some of the stenophylls can store water transiently in tubes or channels. The stenophylls presumably play only a minor role in photosynthesis due to their lack or near lack of green lamina; thus reduction of overall photosynthetic area per plant is a consequence of strongly expressed specialization for asexual reproduction in these dioicous mosses. Likewise, reduction in water-retaining capacity per plant is a consequence of reduction in area of the cancellinae of stenophylls. Four of the extreme leaf-dimorphic Calymperes species occur in Malesia and one in tropical America; one of the extreme leaf-dimorphic Syrrhopodon species occurs in Malesia, three in tropical America, one in eastern North America, and one in eastern Africa (including the island of Mauritius).
This investigation of the phylogeny of the lichen genus Parmotrema (Parmeliaceae) includes 43 of approximately 300 species. It also includes one species each of Canomaculina, Rimelia and Parmotremopsis, and two each of Flavoparmelia and Cetrelia, the last being used to root the tree. A parsimony analysis of 54 morphological and chemical characters resulted in 32 most parsimonious trees. The strict consensus tree is largely resolved and shows all terminal taxa, with the exception of the two Cetrelia species, forming part of the ingroup. However, the results were not strongly supported by a bootstrap test and hence should be interpreted with caution. Nevertheless, the very uncertainty of the results indicates that these traditionally used characters, which have been the basis of the classifications of this group to date, are not helpful discriminators at this level. Due to the weak support of the branches, we make no formal proposals, but the parsimony analysis indicates that Rimelia and Canomaculina may be better treated as subgenera of Parmotrema.
A densitometric technique was developed that permitted rapid quantification of lichen compounds separated by thin-layer chromatography. Thin-layer plates were scanned in a densitometer using a UV light source and density-dependent absorbance or fluorescence was measured for each compound. The lichen products tested differed with respect to photostability under UV, and thus in the time taken to achieve constant densitometric readings. Minimal exposure times required for stabilization of the compounds tested ranged from 3 min to 2.5 hr.
Study of the morphology and chemistry in a large series of specimens from southern Africa has resulted in the recognition of ten new species of Neofuscelia and one new species of Paraparmelia. Additional notes on the chemistry, morphology, or distribution are given for 40 other species, and one new combination is made.
Bryophyte and vascular plant fragments were obtained from late-spring snowbeds at three localities in the Adirondack Mountains, New York. Fragment diversity in samples at alpine and krummholz sites far exceeded that at a forested site, and the diversity of bryophyte species represented by the fragments surpassed that of vascular plants. Approximately 82% of all bryophyte fragments found were in sufficiently good condition to permit identification to species or genus. Statistically significant differences in fragment species diversity occurred between the alpine sites and the forested site, but not between the two alpine sites. The consistent presence of liverworts in the alpine samples indicates that their absence from late-glacial sediments may be due more to taphonomy than either an absence of hepatics from the late-glacial flora or an inability of hepatics to disperse by gametophyte fragments. We detected only a few allochthonous fragments in our samples, and these were of bryophyte species characteristic of lower elevation balsam fir and red spruce-balsam fir forests. In alpine tundra, winter-dispersed fragments of bryophytes may serve as vegetative diaspores, providing a mechanism for rapid establishment of new populations every year following snow melt.