Abstract: The nature of the lichen symbiosis is not clear. It is generally thought to be mutualistic but this concept is not supported by experimental evidence1. Early workers2,3 considered that .lichens represented algae parasitized by fungi—as evidence, they noted algal cells in a lichen thallus that were dead or penetrated by fungal haustoria. Others, however, cited the seemingly healthy and long-lasting nature of lichens as evidence of mutualism. As we report here, our observations of artificial syntheses of the mycobiont Cladonia cristatella (‘British soldiers’) with different algae suggest that the relationship in this lichen is one of controlled parasitism. The mycobiont formed squamules mostly with algae related to its natural phycobiont, an indication perhaps of a long period of co-evolution between the symbionts of this lichen.

Abstract: The effect of morphology on water uptake was examined in eleven species of lichen and three species of moss, using a "raining" wind tunnel environment. Experiments were conducted using a variety of species to test for the influence of specific morphological features such as rhizines, isidia, papules, apothecia and lamellae, in the control of water uptake and storage. Experiments were also conducted to test for the effect of variation in overall morphology on water uptake in lichens and mosses. The results show that rhizines play a major role in the water relations of some species, but not in all. Apothecia in Umbilicaria muhlenbergii have no role in water uptake, nor do the surface papules of U. papulosa or the surface isidia of U. deusta, although the lamellae of U. muhlenbergii are exceedingly important. The upper and lower cortices of lichens were also shown to have a variable capacity for water absorption. The variation in the amount of time required to achieve saturation was the same in the lichens and mosses. This time varied from three minutes in P. juniperinum to over 300 minutes in Stereocaulon saxatile. Plants with a large surface area to weight ratio absorb water at an exceedingly rapid rate. Conversely, any poikilohydric plant showing a low surface area to weight ratio absorbs water very slowly. Variation in the morphology of lichens has been shown to control evaporative water loss (Larson 1979; Larson & Kershaw 1976) in a fashion similar to the way in which variation in leaf or stem morphology controls water loss in many higher plants. These studies are the only ones to date, however, that demonstrate this feature of the biology of lichens. In general, the earlier literature is composed of studies demonstrating, through a variety of techniques, that water loss and gain in lichens, and to a lesser extent in mosses, is a passive phenomenon, and that adaptations do not exist for controlling the plant's water balance (Blum 1973). The techniques used in the past to study water loss and gain tend to fall into two categories: first are immersion experiments in which lichens or mosses are either soaked thoroughly, then allowed to dry in still air (or conversely are plunged into water when dry, followed by measurement of the plant's wet weight as imbibition occurs); second are "bell 007-2745/81/1-15$1.75/0 This content downloaded from 157.55.39.192 on Sun, 28 Aug 2016 04:41:35 UTC All use subject to http://about.jstor.org/terms 2 THE BRYOLOGIST [Volume 84

Abstract: SUMMARY (1) In 1911 and 1925 reindeer, Rangifer tarandus L., were introduced to the subantarctic island of South Georgia, where there is a species-poor vascular flora and no interspecific competition. (2) Snow cover limits the choice of forage almost exclusively to coastal tussock grass, Poa flabellata, for up to 3 months, and certain forage species remain unavailable for up to 6 months. (3) During summer reindeer select forage species high in N and P, notably Deschampsia antarctica, Acaena magellanica and the alien Poa annua. (4) Native species (lichens and A. magellanica) responded quickly and unfavourably to grazing, but tussock grassland was affected only at high population densities. (5) This contrasts with the sequence of overgrazing by introduced herbivores on other subantarctic islands, where tussock grassland has been the most susceptible vegetation type. (6) This dependence on tussock grass, rather than lichens, for winter forage is a major reason for the absence of a population crash.

Abstract: The Antarctic climate is so severe that, apart from two species of flowering plants, terrestrial vegetation is restricted to lichens and mosses (Holdgate 1977) lithic algae (Friedman and Ocampo 1976; Friedman 1977, 1978) and soil algae (Kol 1970; Cameron 1972). Only in the lakes, where organisms are protected from the extremely low temperatures, low humidity, sand abrasion, and freeze-thaw cycles, does life flourish. Nevertheless, although Antarctic saline lakes do support algae and other organisms, and although their populations may be large in some lakes, the range of species is generally much smaller than in lakes of similar salinity in temperate regions.

Abstract: The phycobionts of 20 different lichens were studied in culture, described and assigned to species of Pseudotrebouxia and Trebouxia . Identical phycobiont species were isolated from widely different lichens which showed that these algal symbionts were not specific to particular mycobionts. There was much variation in cellular detail within individual algal species indicating that the criteria currently used to separate species of these phycobionts may be too restrictive.

Abstract: The carbon isotope ratios were measured for six species of lichens and seven species of mosses in northern Michigan. All species appear to utilize C3 photosynthesis to take up atmospheric C02. The lichens had a mean isotope ratio that was 2.4%o more positive than the mean value for the mosses, and the difference was significant at the 0.01 level of probability. It is now clear that among vascular plant species there are at least two genetically determined alternative pathways for the photosynthetic conversion of atmospheric CO2 into carbohydrate. Both the C4 photosynthetic pathway and Crassulacean acid metabolism (CAM) have evolved in a number of vascular plant families. In all studied cases, these two alternative photosynthetic pathways have evolved in lineages derived from taxa that utilize only Ca photosynthesis in the uptake of atmospheric CO2. It appears that the two pathways are of adaptive value in environments characterized by high temperatures and lack of available moisture. In both of these derived pathways, phosphoenolpyruvate car- boxylase (PEP carboxylase) functions as the initial carboxylase of atmospheric CO2, in the light in C4 plants and in the dark in CAM plants. Plants that utilize only PEP carbox- ylase have stable carbon isotope ratios (813C values) of approximately - 12%o (PDB scale).1 In contrast, plants that utilize ribulosebisphosphate carboxylase (RUBP carboxylase) have 813C values of approximately -27%o. Many mosses and lichens grow in microhabitats that can have periods of severe drought of varying durations. There has only been one previous survey of the 813C values of bryophytes over a range of habitats. All of the species in that study (Rundel et al. 1979) exhibited 813C values indicative of C3 photosynthesis. The purpose of the present study is to extend the survey of 813C values to include moss and lichen species and habitats not sampled previously.

Abstract: The effect of pH 5-8 and lichen acid concentration gradients (2.7 x 10-3 2.7 x 1o-6 M) on the toxicity of the following lichen acids: usnic, lecanoric, evernic, vulpinic, stictic, fumarprotocetraric, psoromic, and atranorin, on spores of Funaria hygrometrica was tested. Percent germination and sporeling growth were used as indicators of toxicity. None of the lichen acids were significantly toxic, for either percent germination or sporeling growth at concentrations equal to or below 2.7 x 10-5 M at pH 7.0, but many of the lichen acids which increased in toxicity at values different from pH 7 may have been toxic at lower concentrations if a different pH was used for the assay. Lichen acid toxicity showed a good correlation with pH for the parameter of spore germination, or sporeling growth, or both. Some lichen acids did not inhibit germination but were effective in retarding sporeling growth, or vice versa. This observation is discussed in relation to changing fatty acids and other lipid composition as germination occurs. Two of the three O-methylated lichen acids (evernic and psoromic) were among the most effective in inhibiting growth over all, but at lower pH values these were less effective than non-O-methylated lichen acids. Stictic, which is also an O-methylated lichen acid, was the least effective inhibitor over all the pH values for both parameters, while vulpinic was the most toxic over all the pH values. The order of relative toxicity for the lichen acids is different, depending on the pH and concentration at which they are tested and depending on the parameter measured. Thus, in an ecological sense, it is difficult to evaluate the adaptive significance of a particular compound or group of compounds without knowing what factors influence the toxicity of those compounds and how these factors vary in the organism's habitat. LICHENS produce a number of chemically diverse secondary products known as lichen acids, of which many are unique to lichenized fungi. These can be found in concentrations as high as 25% of the dry weight of the lichen thallus but more typically 5-10% of the dry weight. A single lichen thallus may produce several different acids. The majority of the compounds are depsides and depsidones but other classes of compounds also exist (Culberson, 1969). Lichen acids are found crystallized on the outer surface of the medullary hyphae of the mycobiont in the lichen thallus. In this position they are readily available to the environment, as well as to systematists who wish to extract them in a simple quick manner. Aside from their usefulness in systematics, lichen acids have been postulated to have several natural roles. These roles include biochemical weathering of rock surfaces, acting as sun-screens to protect the phycobiont from 1 Received for publication 20 December 1979; revision accepted 8 April 1980. We would like to thank Drs. Page W. Morgan and Robert S. Egan for helpful suggestions during the conduction of the experiments and for critical reading of the manuscript. Reprint requests should be sent to the second author. intense radiation, and acting as allelopathic agents against both plants and animals (cf. review by Rundel, 1978). Many studies have dealt with the toxic potential of lichen acids. Some have been shown to retard the growth of gram-positive bacteria (Vartia, 1973), several pathogenic and decay fungi (Henningsson and Lundstrom, 1970; Vartia, 1973), and mycorrhizal-forming fungi (Brown and Mikola, 1974). Symbiont and non-symbiont algae, as well as growth of vascular plants, also are retarded by lichen acids (Follmann, 1965; Follmann and Villagran, 1965; Kinraide and Ahmadjian, 1970; Huneck and Schreiber, 1972; Lawrey, 1977). While most lichen acids are effective in most assays conducted, differing reports of relative toxicity have emerged from the data. Where comparisons were attempted, the relative toxicity of many of the lichen acids was different from assay to assay and changed as concentration was changed. Recently, Lawrey (1977) suggested that certain lichen acids (0-methylated), which are considered evolutionarily advanced, are of greater ecological significance than the hydroxylated counterparts. The data on toxicity of lichen acids to bacteria would bear out such a hypothesis (with notable ex-

Abstract: In general, the rate of nitrogen fixation decreased when the lichen Peltigera canina (L.) Willd. was exposed to sulfur dioxide gas at levels from 0.1 to 500 ppm; at 30 ppm, however, nitrogen fixation was stimulated. Chlorophyll content decreased as level of sulfur dioxide increased. A NEGATIVE CORRELATION exists between the degree of air pollution in or near a city or other industrial site and the abundance of lichens. Sulfur dioxide is a very common pollutant and is reported to be especially injurious; probably the absence of lichens in cities and industrialized areas is due to an interaction between sulfur dioxide and other factors characteristic of urban environments such as other gaseous and airborn pollutants, changes in air temperature and humidity, and over all vegetative cover (Pearson, 1973). Dried lichens are generally able to survive high sulfur dioxide concentrations in their surroundings without damage, suggesting that sulfur dioxide is most active in aqueous solution (Nash, 1973; Turk, Wirth, and Lange, 1974). Many of the experiments performed on lichens with aqueous solutions of sulfur dioxide have demonstrated a correlation between aqueous

Abstract: Biomass was estimated in stands at about 600 m elevation. Epiphytes were divided into three categories: lichens with blue-green phycobionts, lichens with green phycobionts only, and bryophytes. Total biomass was 3500 kg ha-1: 1220 kg ha-1 for lichens with blue-green phycobionts, 5300 kg ha-1 for lichens with green phycobionts only, and 1770 kg ha-1 for bryophytes. Nitrogen-fixing lichens can play an important role by naturally fertilizing forest com- munities. Although they often represent a negligible portion of the total biomass, they may provide much of the newly fixed nitrogen (Pike 1978). Previous studies of communities of nitrogen-fixing lichens have been done in old-growth conifers of western Oregon (Denison 1973; Pike et al. 1977), in oak and ash forests of North Carolina (Becker et al. 1977), and on various ground-dwelling species in sub-polar regions (Alexander 1975). An unusual community of epiphytes on Abies lasiocarpa (Hook.) Nutt. (subalpine fir) on a Mt. Baker, Washington, lava flow appeared to contain large quantities of diphyco- philous and cyanophycophilous lichens. These species have blue-green-algal phycobionts and presumably fix atmospheric nitrogen. The study reported here was designed to esti- mate the biomass of these lichens and the associated chlorophycophilous lichens (with green-algal phycobionts only) and bryophytes.

Abstract: SUMMARY Thalli of Peltigera membranacea, Peltigera polydactyla and Lobaria pulmonaria were labelled with 15N and subjected to simulated episodes of heavy rainfall after periods of drying in a lighted air-conditioned incubator. Inorganic and total nitrogen was estimated in the eluates. The drying-wetting cycle was repeated three times. From the level of 15N labelling of the eluates, it was evident that recently fixed nitrogen was released, the inorganic fraction (NH4+) being up to three times more heavily labelled than the organic. The amounts of nitrogen lost in successive episodes generally diminished in logarithmic fashion, the level of labelling remaining approximately constant, implying little or no replenishment of mobile material from insoluble reserves. Up to three times the total nitrogen fixed per day could be lost in one rainfall episode. A preliminary trial showed that nitrogen losses from thalli under less rigorous regimes could be of nutritional benefit to the underlying moss substratum.

Abstract: Elemental compositions of two epiphytic Okefenokee Swamp lichens, Usnea and Parmelia, were examined. Differences between the two genera are ascribed to morphological and metabolic characteristics. These lichens occupy the same habitat in Okefenokee; therefore, elemental composition should reflect niche separation that allows the two genera to coexist. The fruticose lichen, Usnea, appears to depend more on atmospheric wetfall than dryfall, having higher concentrations of dominant precipitation elements (Na, Ca, Mg). The foliose lichen, Parmelia, appears to depend more on atmospheric dryfall than wetfall, having higher concentrations of dustfall elements (P, Si, Al, Fe, Zn, K). Substrate composition affects both lichens through either stemflow or direct substrate uptake. Elemental concentrations in Okefenokee lichens are similar to those of epiphytic lichens found elsewhere. Differences between genera are greater than differences between locations in Okefenokee. Lichen elemental content has become only recently a topic of interest in lichen research. The discovery that lichens concentrate pollutants has inspired researchers to look more closely at the role of lichens in ecosystem mineral cycling (Pike 1978; Lang et al. 1976; Touminen & Jaakkola 1973). Epiphytic lichens are inconspicuous components of most temperate forest ecosystems; however, in freshwater swamps, which can provide ideal habitats for epiphytic growth, lichens are often abundant and may play more important ecosystem roles. Much attention has been given to the abilities of lichens to absorb elements from their nutrient-poor environments; many lichens maintain greater concentrations of elements than do sympatric, terrestrial plants because of more efficient uptake mechanisms and longevity (Lounamaa 1965). Lichens are known to accumulate various trace elements and have been studied as effective pollution indicators and collectors of atmospheric radioisotopes (Jenkins & Davies 1966). Although lichen elemental composition has often been studied in terms of atmospheric pollution, little is known about the elemental content of epiphytic lichens in undisturbed ecosystems (Touminen & Jakkola 1973). This study examines distributions of 18 elements in two epiphytic lichen genera, Usnea and Parmelia, from Okefenokee Swamp. Differences in the morphological characteristics of the two genera, in substrate type, and in location within Okefenokee Swamp are hypothesized to account for much of the variation in elemental composition. Different species of epiphytic lichens often occupy the same habitat and partition their common nutrient environment by uptake characteristies, substrate preferences, and morphological adapta007-2745/81/48-58$1.35/0 This content downloaded from 157.55.39.249 on Wed, 03 Aug 2016 05:05:52 UTC All use subject to http://about.jstor.org/terms 1981] BOSSERMAN & HAGNER: ELEMENTAL COMPOSITION 49 tions. Among fruticose, crustose and foliose lichens, morphological differences that affect exposure to their environments should be reflected in elemental composition. In Okefenokee Swamp, Parmelia and Usnea coexist on dead and living branches of numerous Okefenokee trees and shrubs. Usnea is a fruticose or "beardlike" lichen with a stringy body that hangs from a single point of attachment. Usnea greatly depends on atmospheric factors because of its large surface area exposed to air. Atmospheric moisture dominates Usnea's ecology, hence the common name "fog lichen." Usnea is particularly sensitive to air pollution, making it an effective indicator of environmental conditions (Ferry et al. 1973). Although Usnea is attached to bark with fungal strands that penetrate cracks and lenticels, it apparently receives no nutrition through its basal holdfast (Brodo 1973). The most common Usnea species present in Okefenokee are U. florida (L.) Web., U. longissima (L.) Ach., and U. strigosa (Ach.) Eaton. Parmelia, on the other hand, is a foliose lichen, having a flat, leaflike thallus, which extends along branches and trunks of trees. Parmelia has more contact with its substrate than does Usnea, which has only a small basal holdfast. Usnea's thallus consists of numerous, long, thin cylinders, a form exposing to the atmosphere more surface area per unit biomass than does Parmelia's flattened thallus. Parmelia is attached to its substrate by numerous penetrating rhizines, but these apparently do not absorb nutrients from the substrate (Brodo 1973). Parmelia's gray thallus is comprised of numerous cup-like apothecia and depressions, suggesting an ability to accumulate atmospheric dryfall and wetfall. Rocks and trees in habitats are substrates for the cosmopolitan Parmelia. The most common Parmelia species in Okefenokee is P. perforata (Jacq.) Ach. METHODS AND SITE DESCRIPTION Okefenokee Swamp is a large wetlands area in southeastern Georgia and northern Florida, comprised of shrub swamp (34% of the total area), cypress forests (23%), aquatic macrophyte and grass sedge marshes (21%), and bay forests (6%) (Hamilton 1977). Study sites were chosen in aquatic-marsh shrub-swamp ecotone areas abutting Grand, Chase, Chesser, and Durdin Prairies and Billy's Lake. Lichens of the genera Parmelia and Usnea were collected from shrubs (angiosperms) and cypress (gymnosperms) from three randomly selected sites in these areas. Dominant shrubs included Cyrilla racemiflora, Ilex cassine, Lyonia lucida, Leucothoe racemosa, and Clethra alnifolia, with Cyrilla and Ilex being most abundant. Immature pond cypress (Taxodium distichum var. nutans) are intermixed with shrubs. In the laboratory, Usnea and Parmelia were separated from their respective cypress and shrub substrates; care was taken to remove as much bark as possible from lichens. Sorted lichens and their substrates were dried at 60'C in a forced air drying oven and ground with a Wiley mill. Half-gram samples were ashed at 500'C in a muffle furnace, dissolved in a 20% nitric acid solution, and analyzed with a Jarrell Ash plasma emission spectrograph for 18 elements: P, K, Ca, Mg, Fe, Mn, B, Cu, Zn, Na, Al, Si, Co, Cr, Ni, Pb, Cd and Sr. Orchard leaf standards from the National Bureau of Standards were used to calibrate the spectrograph. Interferences from the ionic matrix were examined by making standard additions of the measured elements to a single plant sample (Bosserman 1979). All elements in the sample were above the detection limit of the instrument. More information about detection limits, matrix interferences, machine variability, and percent recovery for this method and this particular instrument are being published elsewhere (Blood et al. 1980; Blood, pers. comm.). Combined wet and dry precipitation samples in various Okefenokee locations were collected in polyethylene containers over two week periods during the year preceding the sampling period. The precipitation samples were concentrated on a hotplate, placed in a 20% nitric acid solution, and analyzed for the above 18 elements on the plasma emission spectrograph. Water samples with known concentration were used to calibrate the instrument (Blood et al. 1980). Statistical analyses were done using SAS 76 (Barr et al. 1976). Analysis of variance and correlation analyses were done using GLM and CORR procedures, respectively. Duncan multiple range tests were used to describe significant differences among means (0.05 level). Genus, substrate type, and location were factors included in a statistical model, in which a percentage of element content variThis content downloaded from 157.55.39.249 on Wed, 03 Aug 2016 05:05:52 UTC All use subject to http://about.jstor.org/terms 50 THE BRYOLOGIST [Volume 84 TABLE 1. Elemental concentrations (ppm) of Usnea and Parmelia from Okefenokee Swamp. Values are means from all locations and substrates. * P(Ho:equal means) < 0.01, ** < 0.001, *** < 0.0001. Usnea (ppm) Parmelia (ppm) ? (SD) i (SD) Element n = 40 n = 43 Usnea concentrations greater than Parmelia Ca 3600 (1300) 2000 (1300) *** Mg 810 (170) 410 (210) *** Na 240 (50) 160 (60) Sr 15 (4.1) 10 (4.1) *** Parmelia concentrations greater than Usnea K 1500 (230) 2000 (470) *** Fe 290 (70) 370 (90) *** B 13 (6) 32 (33) ** Zn 23 (4) 31 (7) Al 440 (110) 760 (240) *** Si 310 (39) 360 (100) * P 190 (30) 320 (90) Usnea concentrations same as Parmelia Ash 19,000 (6000) 26,000 (2700) Mn 64 (22) 71 (59) Cu 4.7 (0.9) 5.6 (3.3) Co 0.3 (0.12) 0.2 (0.20) Cr 1.0 (0.3) 0.8 (0.4) Ni 1.2 (0.3) 1.3 (1.5) Pb 29 (7.0) 31 (10.3) Cd 0.3 (0.1) 0.3 (0.2) ability is attributed to each factor. From this model, the relative importance of elemental sources and the influences of generic differences, substrate type and location are established.

Abstract: The comparative digestibilities of plants and their rates of digestion in vitro were assessed by fermentation with ruminal fluids obtained from barren-ground caribou ( Rangifer tarandus groenlandicus ) shot on their winter range in the southern Northwest Territories. There was a near-linear increase in the in vitro, dry-matter disappearance (IVDMD) with fermentation time (30-120 h) for all eight lichen species that we tested. In contrast, IVDMD was essentially maximal after 60 h fermentation for 10 of 11 non-lichen species. The green leaves of Carex rostrata and Equisetum variegatum were the only species with IVDMDs higher than 50% after a 60-63 h fermentation period. The two species of mosses and a liverwort were poorly digested (15-27%). The addition of 63 mg of urea to each tube markedly increased the digestibilities of both species of lichens tested, and that of Vaccinium vitis-idaea , but it lowered the IVDMD of Salix and Betula stems and the green and cured parts of Carex rostrata . The IVDMDs of four lichen species collected on the Canadian Arctic Islands were higher than those of eight terricolous species obtained from the mainland winter range of R. t. groenlandicus. Key words: Rangifer , caribou, in vitro , digestibility, forages, lichens, rates, Canada

Abstract: The value of terricolous lichens as bioindicators of industrial metal fallout patterns is investigated; the widely-known inverse relationship between the metal content of lichens, as well as their associated soils, and the distance from the pollution source was found to be affected by microclimatic factors dependent upon soil surface topography and the local vegetation. Samples of lichen vegetation and their associated soils from Risby Warren, North Lincolnshire, were analysed for Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Enhanced concentrations of Fe and Mn in the lichen, soil and air samples were indicative of their emission from the nearby Scunthorpe steelworks. The highest concentrations of all metals analysed were found to be in the top layer (0-5 cm) of the soils.

Abstract: Over 8000 lichens representing 405 taxa were collected at 128 dif- ferent localities during 11 weeks collecting in the park in 1978 and 1979. Several areas of special interest to the lichen flora are noted. Eighty-eight new state records were found within these collections and all but eight of the species collected by Bruce Fink in 1901 were recollected. Three new records for North America were identified: Arthonia fuliginosa (Turn. & Borr.) Flot., Chaenothecopsis savonica (Riis.) Tibell, Lecidea epixanthoidiza Nyl. Lichens for winter food for caribou would probably not be a limiting factor in the success of any reintroduction of woodland caribou to the park. The scarcity of Xanthoria elegans was studied and is probably due to lack of wave splash. The lichen flora is rich in fruticose lichens, which suggests that no air pollution is present. The lichens of Minnesota have not been studied much since Bruce Fink's work near the turn of the century (Wetmore 1978). A few lichenologists have visited the state recently but little new information on the lichens has been published since Fink's Lichens of Minnesota (Fink 1910). For the past ten years I have collected in many areas not visited by Fink, and have revised the lichens in the University of Minnesota herbarium as part of several lichen projects within the state. As a result, numerous new records have turned up and about 85% of the names in Fink's 1910 paper have been changed. One of the most extensive studies done was this lichen flora of Voyageurs National Park. Voyageurs National Park lies along the northern border of Minnesota adjacent to Can- ada and extends for 32 miles along the boundary just east of International Falls. The park was officially established in 1975 and development of the park is still underway. The vegetation of the park is typical southern boreal forest. Most of the park has been logged and burned at least once beginning about 1910 but a few small areas remain that were never cut. A large part of the park has regrown to quaking aspen (Populus tremuloides Michx.) and white birch (Betula papyrifera Marsh.), especially in places with deeper more moist soil. Dry rock outcrops occur frequently and are surrounded by jack pine. (Pinus banksiana Lamb) (Fig. 1-2). Jack pines are also common on ridgetops and areas with thin, dry soil and in a few of these areas stunted red oak (Quercus rubra L.) is found in open stands. A mixture of red pine (Pinus resinosa Ait.) and white pine (Pinus strobus L.) grow in some localities but large old trees are found only in buffer zones along a few of the large lakes and in a few places not logged during the most recent timber operations. Moist hillsides may have black spruce (Picea mariana (P. Mill.) B.S.P.) with or without balsam fir (Abies balsamea (L.) P. Mill.), but, due to logging, fires and insect damage, there are no large stands of balsam fir. There are many islands and bays and the lowland bay heads and valleys have stands of eastern white cedar (Thuja occidentalis L.) or black ash (Frax- inus nigra Marsh.) but most of these have also been logged. Black spruce bogs and beaver ponds are frequent in depressions but tamarack (Larix laricina (DuRoi) K. Koch.) is rare.

Abstract: Acarospora isortoqensis Alstrup sp. n. is described. Cornicularia mirabilis Lynge is shown to be synonymous with Endpcarpon pulvinatum Th. Fr. The spores of Muel–lerella frustulosae Vouaux are elliptical rather than spherical. Six lichens and seven lichenicolous fungi are reported as new to Greenland, and new localities are given for two lichens and one lichen parasite rarely collected in Greenland.

Abstract: This study was undertaken because of reports of decreased visibility due to haze and the possibility of increased air pollution in the park. Numerous localities where lichens had been collected 10 years ago were revisited in 1980 to look for any changes in the lichen flora. Photographs were taken from scenic vistas where photographs had been taken earlier. Permanent photographic points for lichens were established for long term monitoring. It is argued that fruticose li- chens are just as useful for monitoring air quality in arid areas as in wetter areas. There has been no loss of lichen species at any locality over the past 10 years and haze conditions have not changed much. It is concluded that no significant increase in air pollution has occurred within the park over the past 10 years. In 1966, 1969 and 1970, complete lichen collections were made at 38 localities in Big Bend National Park. Label data for all collections are stored in a computer data base at the University of Minnesota (Wetmore 1979) and a report on the macrolichens (foliose and fruticose lichens) from these localities has been published (Wetmore 1976). Even though the general climate in the park is quite dry, several species of fruticose lichens were found at numerous localities in the mountains. At the time these collections were made, color photographs were taken from various scenic vistas throughout the park. Recent observations by various people have reported the visibility in the park has been degraded due to increased haze conditions. There has also been concern that the haze might be associated with air pollutants that could damage the vegetation of the park. Possible sources of the air pollution are Carlsbad, New Mexico, and El Paso, Texas, These cities are about 400 km northwest of the park and wind patterns are such that air masses from these cities could blow into the park. Lichens are slow growing and remain alive for many years, and therefore can be used as long-term indicators of air quality. They are also known to be very sensitive to many atmospheric pollutants. Some lichens are damaged or killed by low levels of sulfur dioxide (0.5 ppm, Nash 1973), nitrogen oxides (2-4 ppm, Nash 1976) and other strongly oxidizing compounds (Nash 1972, 1975; Ferry et al. 1973). The algae of the thallus seem to be the

Abstract: Also included is an erratum for the article “Seasonal Vegetative Establishment and Shoot Reserves of Eastern Gamagrass.”

Abstract: The minimal area of two lichen saxicolous-calcicolous communities (subassociation with Caloplaca tenuatula of Aspicilietum calcareae and typical Verruearietum cazzae) is studied by means of various methods: - the method of the species-area curve, - the Cain and Castro method, - the Boudouresque and Belsher method, - the method of the mean similarity-area curve (Gounot and Calleja).

Abstract: The fungus vegetation, the vegetation of phanerogams, mosses, and lichens, the soilprofiles are described and soil chemical analyses are made in the associations Dicrano-Quercetum, Querco-Betuletum, Violo- Quercetum, and its sub-association ilicetosum (sub-ass. nov.) in the province of Drenthe (NorthEast Netherlands). New methods are applied in the soil chemical analysis (amount of ions expressed in mass concentration, calculation of total ion supply), in the vegetation analysis (separate analysis of the moss synusia on rotten tree stumps and dead wood), and in the mycosociological analysis (determination of spatial frequency). The last-named method is used for the determination or estimation of the abundance of the mycelia per species, of the plot homogeneity, of the pattern of the species, and of the correlation between species. Based on the phytocoenose the Querco-Betuletum and the Violo-Quercetum appeared to be closely related, and to belong to the alliance Quercion robori-petraeae. It was confirmed that the Dicrano-Quercetum is less related, and did not belong to this alliance. In the soil there are differences between the syntaxa in the profiles and in the 'total ion supply'. The syntaxa have many differential species among the fungi in a way to support the concepts on the affinities based on the phytocoenoses. The 'minimal area' of the fungus vegetation was determined. Distribution patterns of fungus species within plots are discussed. Annotations on identifaction and taxonomy of fungi are given; a new fungus taxon is described: Psathyrellafulvescens var. dicrani .

Abstract: Hyphomorpha, a genus of theStigonematales, is confirmed to be a phycobiont in twoSpilonema species (Coccocarpiaceae). The morphology of the symbiotic algae inSpilonema dendroides andS. schmidtii is described. The phycobiont inS. dendroides is possiblyHyphomorpha antillarum, the alga inS. schmidtii might be a species related toH. perrieri. New localities for the rare lichens are reported: Alaska forS. dendroides and Ceylon forS. schmidtii.