Abstract: Summary The loss of water by evaporation in various species of lichens has been examined under a range of controlled windspeed/radiation regimes. Temperate and arctic species both show a type of morphological control of evaporation. Such control varies, however, with the nature of the surrounding environment. Evaporation from those species which show a very low resistance to evaporative water loss such as Bryoria nitidula, Umbilicaria deusta and U. veiled appears to be relatively insensitive to increases in radiant flux. Conversely those species, or specific growth forms, which show a high resistance to evaporative water loss, such as Cladina stellaris and U. muhlenbergii, appear to be sensitive to increases in supply of radiant energy. These results suggest that the morphological control of evaporation in lichens is significant to the ecology of this group of plants.

Abstract: A review is presented of plant community ecology within the Antarctic Botanical Zone. The vegetation is formed largely of mosses, lichens, and algae but hepatics also occur and two native species o...

Abstract: Anaktuvuk Pass in the central Brooks Range of northern Alaska provides a major migration route for the western arctic caribou herd. A por- tion of the herd overwintered in the Anaktuvuk Pass area 8 years prior to sampling. Caribou grazing resulted in the almost complete removal of mac- rolichens in grazed areas and this has been followed by the invasion of crus- tose and squamulose species. An analysis by species biomass composition for grazed and nongrazed areas on both north and south slope exposures revealed a lichen composition of 31 species, with Cladonia stellaris, C. rangiferina, C. arbuscula and C. mitis being the most common and present in almost equal abundance on both exposures. In addition, 288 species in 71 genera are re- ported for the Anaktuvuk Pass area. Aspicilia plicigera (Zahlbr.) Thoms. is reported as a new combination and new to North America. Tundra occupies approximately 15% of the earth's land surface, principally con- fined to the northern portion of the Northern Hemisphere (Bliss, 1971). These vast treeless expanses are dominated by prostrate shrubs, short-stemmed herbaceous pe- rennials, lichens and mosses (Billings, 1973). The lichens are particularly important in upland portions of tundra systems where they form extensive mats (Thomson, 1972) that are utilized by caribou and reindeer as a winter food source (Hanson, 1966a; White et al., 1975). Although lichens are more diverse than higher plants in the arctic, most ecological studies have been conducted on higher plants. Lichens are capable of existing in this heat deficient ecosystem, in part because they are highly resistant to frost injury and can survive long periods of inactivity while in a frozen state (Kap- pen, 1973). Consequently, lichens are opportunistic species which are capable of efficiently using favorable conditions present during the brief summer period for pro-

Abstract: In the region around the Four Corners Power Plant of New Mexico, 159 lichen species in 40 genera are recorded. Although the power plant has operated over 10 years, no marked gradient in species composition or lichen cover data were evident in relation to the power plant. Eight desert lichen species are shown to be sensitive to 0.5 ppm SO/sub 2/ when moist but are insensitive when dry. Because of the aridity of the climate the lichens are probably rarely susceptible to SO/sub 2/ injury. In addition the lack of pattern probably reflects the dominance of resistant crustose growth forms in the lichen flora and the fact that ground level SO/sub 2/ concentrations are relatively low even though SO/sub 2/ emissions are relatively high.

Abstract: Lichens which grow as clones or large anastomosing mats are often hard to handle experimentally because of the difficulty in defining an individual plant. Lichens in the Umbilicariaceae, however, are normally monophyllous and thus may be more convenient experimental material for the study of physiological ecology. In this study, the response of five species of Umbilicaria to a variety of experimental treatments is examined to determine the suitability of using such plants as an experimental system in physiological ecology, when using the ‘discrete sampling’ method of infrared gas analysis. The treatments used included the time-course response of net CO2 exchange following resaturation, the effect of ventilation, the response to the concentration of CO2, the response to irradiance, and the response to a low temperature pretreatment. The species could be considered suitable if steady-state rates of gas exchange extend over a period of several hours, if rates of CO2 exchange were not influenced by ventilatio...

Abstract: delta(13)C values of the lichens Ramalina duriaei and Teloschistes villosus collected in their natural habitat were repeatedly measured during 2 years. Results show variations in the stable carbon isotope ratios ((13)C/(12)C). Such variations are correlated to the seasonal rainfall, i.e. low values of delta(13)C of the lichens during the winter and high values of delta(13)C during the dry summer. Relatively low delta(13)C values were obtained also in laboratory experiments with lichens grown under controlled humid conditions and in lichens collected from humid habitats.The variations in carbon isotopes were associated with quantitative metabolic changes. Under humid conditions an increase was obtained in the total amount of the extracted water-soluble fraction of the plant tissues as well as in the relative content of soluble carbohydrates.Analysis of the possible factors which may cause such variations indicates that the quantity of precipitation and the exposure time to high humidity were the main environmental factors causing seasonal variations in the delta(13)C values of the lichens. Such variations are dependent mainly on enzymic reactions and are probably less influenced by purely physicochemical processes. In view of the data presented here the balance between carboxylation and decarboxylation reactions seems to be the major factor for the observed seasonal differences. Winter accumulation of (12)C enriched components causes an over-all decrease in delta(13)C. During the summer, those storage materials are respired with concomitant increase in the delta(13)C of the residual plant material.

Abstract: The macrolichen vegetation on Pinus sylvestris L., and the contents of S, K, Ca, Ti, V, Fe and Zn in the lichen Hypogymnia physodes (L.) Nyl. and needles of Pinus sylvestris were investigated in relation to air pollution at 55 study stations in and around the industrial town of Valkeakoski, southern Finland. The air pollutants are emitted mainly by the wood pulp industry. The parameters of the lichen vegetation (occurrence of species, number of species, cover of the vegetation and the damage index) did not give a good picture of the distribution of air pollutants, because the environmental conditions were not exactly the same at the different study stations. The accumulation of the elements was more effective in the lichen than in pine needles and the lichen element contents agreed better with the pattern of the prevailing winds. The correlations between the contents of the different pollutant elements were also stronger in the lichen than in pine needles. The most reliable indices of pollutant substances originating from combustion of fuel oil and the wood pulp industry were the sulphur and vanadium contents of the lichen, while the calcium, titanium and iron concentrations of the lichen gave a good idea of the distribution of dust raised from the roads by traffic.

Abstract: The water-soluble polysaccharides isolated from the laboratory cultures of lichen mycobionts and phycobionts were studied comparatively. The polysaccharides of mycobionts so far tested showed close similarities with those of parent lichens, whereas the polysaccharides of phycobionts gave different features. Therefore, it is highly probable that the water-soluble polysaccharides of lichens are mostly produced by their mycobionts as like as the lichen metabolites of smaller molecular size.

Abstract: The aliphatic acids, constipatic acid [2-(14'-hydroxypentadecyl)-4-methyl-5-oxo-2,5-dihydrofuran- 3-carboxylic acid], protoconstipatic acid [2-(14'-hydroxypentadecyl)-4-methylene-5-oxotetrahydro- furan-3-carboxylic acid] and dehydroconstipatic acid [4-methy1-5-oxo-2-(14'-oxopentadecy1)-2,5- dihydrofuran-3-carboxylic acid], have been identified as constituents of various Xanthoparmelia lichens from Australia.

Abstract: Microbial populations associated with the major substrates of the canopy of a single 70 m old-growth Douglas fir were studied to determine potential activities. Seasonal samples from bark, foliage, epiphytic moss, lichens, and litter accumulations were collected to: (a) obtain population data, (b) isolate the major groups of microorganisms present, (c) measure enzymatic activities associated with cellulose and xylan degradation, and (d) examine the potential for nitrogen fixation. We tested 562 bacterial isolates for utilization of 25 compounds associated with the canopy substrates, and for activities in nitrogen and sulfur cycle transformations. Total bacterial populations, reflecting seasonal temperature and moisture conditions, were lowest on bark and foliage [21–266×103 colony-forming units (CFU/g)] and highest on moss and lodged litter (19–610×105 CFU/g). Lichens contained intermediate numbers of bacteria (3.3–270×105 CFU/g). The majority of the bacteria were classified as species ofArthrobacter, Bacillus, Flavobacterium, andXanthomonas. Isolates ofAlcaligenes (Achromobacter), Aeromonas, Chromobacterium, Micrococcus, andPseudomonas were less common. No measurable rates of nitrogen fixation attributable to free-living bacteria were detected by acetylene reduction. Eleven species in six genera of lichens containing a blue-green algal phycobiont showed positive acetylene reduction. One species,Lobaria oregana, accounted for 51% of the total lichen biomass of the canopy. Cellulase and xylanase activity was routinely detected in moss and litter samples, and less frequently in lichens. There was a strong correlation between the two activities for moss (r=0.94) and litter (r=0.81).

Abstract: Based on examination of some 700 specimens, the lichen flora of Tristan da Cunha is reported to consist of 82 species. Of these, about 5% are endemics. Approximately 20% of the lichens belong to a Southern Hemisphere element, while about 70% are widespread in their distribution, most of the latter being temperate "oceanic" species. It is suggested that the lichen flora is young in age and the result of long-distance dispersal; mostly Magellanic in origin.

Abstract: Lichen species were sampled at 85 sites within the City of Seattle. These data, expressed numerically, were used to construct a map consisting of five zones which reflected variances in the composition of the lichen flora along air pollution gradients. The topography of the city, land use patterns, and prevailing winds were found to affect the dispersion of air pollutants and therefore the distribution of lichen species.

Abstract: 172 refound a of 37%; the are compared to the Hawksworth and (1970) zones and all species referable to zones 7-10 have been lost from the area now and several in zone 6 are also extinct.] analysed for curium 242 and curium 244 during 1977 to establish their present distribution. indicate a shorter residence time for curium in the lichen than for plutonium immediately after the for use in Normandy and applied to a of the Rouen area in which 10 are mapped. sulphur dioxide limits of species distribution of Lecanora conizaeoides, Hypogymnia physodes Parmelia element levels are iron/titanium ratio is seen to reflect the presence of trapped particulates. Various uptake and release mechanisms are closely examined. Nutritional needs of lichens and their value as food, the mineral sources available, mineral translocation and turnover are surveyed. Lichens are concluded to be favourably equipped morphologically and physiologically [Four zones were mapped in Tokyo Metropolis based on average coverage of lichens on tombstones and corre-sponded well with known sulphur dioxide levels. Sulphur dioxide levels also correlated well with sulphur content of Parmelia tinctorum and P. clavulifera. The formula is proposed: atmospheric SO 2 concentration in p.p.m. = 0-1 x sulphur content (mg) in 100 mg dried P. tinctorum thalli.] Sulfite action on ribulosediphosphate carboxylase in the lichen Pseudevernia 29: 63-66. [The key carbon dioxide fixation enzyme is not more sensitive to sulfite in Pseudevernia furfuracea than in spinach. Lichen sensitivity to sulphur dioxide is concluded to be not enzymatically, but morphologically and physiologically based.]

Abstract: Parmelia queenslandica, Parmelia subtabacina Parmelia norsticticata, Parmelia numinbahensis, Parmelia springtonensis and Parmelia butleri are described as new from Australia The intergradation of Hale's genera Pseudoparmelia and Parmelina is discussed with particular reference to P norsticticata, Parmelia labrosa and Parmelia conlabrosa

Abstract: SUMMARY Eighty-five species from thirty-nine genera are recorded from the Cavalli Islands. Rich lichen floras (dominated by members of the Parmeliaceae, Physciaceae and Ramalinaceae) grow on greywacke rocks in the maritime zone and in grasslands. Scattered clumps of epigean lichens (particularly Cladoniaceae) occur on sparsely grassed ridges and beneath older patches of manuka heath. A rich and diverse flora (dominated by Pannariaceae, Stictaceae and crustose taxa) grows on bark in semi-open canopied, mixed native forest on Motukawanui. A stand of cabbage trees on Nukutaunga supports a less diverse epiphytic flora (mostly Collemataceae in the centre of the grove and Parmeliaceae towards the fringes). A wide variety of lichens occur on old fruit trees and exotic plants in the overgrown homestead garden on Motukawanui. Depauperate lichen floras grow beneath dense-canopied native forest (mostly Collemataceae), on the bark of shrubs at the fringes of petrel scrub (mainly Parmeliaceae, Physciaceae, Teloschistaceae), on the rough bark of pohutukawas and on rocks and clay on exposed cliff-tops.

Abstract: The element concentration of the lichen species Alectoria fremontii and its substrate (bark of Pinus sihestris) were studied. It appeared that the content of all the investigated elements, except for vanadium, was higher in the lichen samples than that in the corresponding bark samples. Analysis-of-variance procedure has demonstrated that the concentration of N, P, S, Se, V, Hg and U in lichen samples appeared to change significantly in samples gathered from two different height-zones on the stems above ground level. However, this was not the case with the bark samples. The elements Se, V, Hg, U, Co and Mo determinations of the samples were performed by neutron activation methods.

Abstract: 25 species of lichens have been collected in semidesertic to desertic areas of Iran. On the basis of spatial relations to the substrate and anatomical features of the thallus three main groups (one with a subdivision based on colour and morphology of the thallus) can be differentiated. Selective advantages and peculiarities in connection with the desert habitat are pointed out, such as inverse thallus-structure, a dense network of skeletal hyphae in the substrate in otherwise epilithic species, proliferating areolae of the thallus, immersed pycnidia with trichogynes and brownish spores in groups with usually colourless spores. Most of the species are wide-spread in arid and often also in humid regions; only one species,Verrucaria buschirensisJ. Steiner, seems to be endemic. The prevalence of cyanophilic lichens in deserts may have phylogenetic reasons, as these groups appear to date back to periods without higher vegetation and a desert-like environment.