Micarea micrococca and M. prasina are two morphologically similar crustose lichens that have been reported from North America. We present the results of the first large scale study of these species, and the first study of them outside of Europe. We examined over 200 specimens referable to these species from eastern North America to determine whether differences in morphology, ecology, or geographic distribution correlated with the differences in chemistry that distinguish the two species. Differences in morphology and ecology were not detected, but geographic distribution was found to be strongly correlated with chemistry. Nonetheless both species are entirely sympatric in the study area. Though overlapping, goniocyst size also appears to correlate with chemistry, a character that has not previously been explored in studies of this group. Treatments for both species are presented, including illustrations and distribution maps.

Biological soil crusts dominated by mosses are commonly found in arid and semiarid areas, where mosses spend large parts of their time in a state of intense desiccation. The effective recovery of moss crusts after long-term desiccation is vital for their survival. In this study, we analyzed the changes in micromorphology, ultrastructure and chemical composition in Bryum argenteum samples desiccated for 1 week or 1 year. We used non-destructive and anhydrous methods of analysis, including scanning electron microscopy, transmission electron microscopy and Fourier transform infrared analysis. After long-term desiccation (1 year), B. argenteum samples showed a rapid recovery of F_V/F_M in the light after rehydration. For the 1-year desiccated samples, the thallus remained intact but shrunken. Within the thallus, cell arrangement was disorderly, cell shapes were irregular, and cell walls were thinner. Inside cells, chloroplasts remained intact, but some thylakoids were degraded. In terms of the major cellular components, the lipid and carbohydrate contents increased, the numbers of α helixes and β sheets in protein secondary structures increased, while the number of turn structures in proteins decreased. The changes in protein secondary structure appear to be an important factor in the tolerance of B. argenteum to long-term desiccation. The recovery mechanisms that function after rehydration include processes for the repair of protein conformation and the re-synthesis of thylakoids.

Because of their unique physiology, lichen communities are highly sensitive to climatic conditions, making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for tracking the effects of climate change in south-central and southeast Alaska. Using 196 plots, we model community composition and 12 individual species abundances in relation to synthetic climate variables. Both types of lichen indicator are closely related to the climate variable describing a transition from warm, wet oceanic climates to cooler, drier suboceanic climates. Lichen communities and individual species exhibited thresholds associated with average December minimum temperatures between −10.2 and −7.8°C and annual precipitation between 106 and 172 cm, suggesting rapid turnover with relatively small changes within these ranges. These climate conditions occur close to the coast in northern portions of the region and further inland in southeast Alaska. Because lichen communities in the threshold region may be most sensitive to a changing future climate, they should be targeted for monitoring efforts.

Rinodina pallidescens is described as a new species, endemic to southern Alaska. Rinodina buckii and R. oregana are discussed in terms of their range extensions and possible phytogeographic histories.

A review of the crustose lichen genus Rinodina in Great Smoky Mountains National Park is presented. Seventeen species are reported from the study area, of which three represent new reports (R. bullata, R. excrescens, and R. oxydata) and one is described as new to science (R. brodoana). Based on current collections, the new species is restricted to old growth hardwoods and occurs at middle to low elevations. Also based on collections information, two species (R. brodoana and R. chrysomelaena) are proposed to have IUCN Red List ranks of critically endangered. We discuss the increasing significance of middle to low elevation habitats in this biodiversity hotspot. All 17 species reported from the study are illustrated, their biogeographic patterns and ecologies are discussed, and maps showing revised North American distributions, are provided. A key to the 21 species of Rinodina known to occur in the southern Appalachian Mountains is also provided.

Two new genera in the Arthoniales are described from the Pacific Islands. Glyphopsis, with the new species G. aurantiodisca from New Caledonia is characterized by a thallus containing divaricatic acid and zeorin and sessile grouped ascomata with bright orange discs and raised lecanorine margins, and the ascospores hyaline and muriform. Gossypiothallon, with the new species G. appendisporum from the Solomon Islands is characterized by a byssoid thallus containing zeorin and pedicillate, simple ascomata with pale pink discs, without differentiated margins and hyaline, bacillar, 3-septate ascospores with two polar, usually curved gelatinous appendages. Eight further corticolous crustose lichens are described from either New Caledonia or the Solomon Islands. Byssoloma xanthonicum is characterized by a thallus containing norstictic acid and lichexanthone and 3-septate ascospores. Cliostomum ovocarpum has orange yellow, convex apothecia and 1-septate ascospores. Crocynia minutiloba has palmately branched lobes on a thick whitish byssoid hypothallus and flat lecideoid apothecia. Megalotremis dolabarata has superficial cylindrical grey pycnidia and simple ellipsoid conidia. Pyrenula filiformis has a thallus with pseudocyphellae covering most part of the ascomata and 11–17-septate, slender fusiform to slightly clavate ascospores. Pyrenula mastigophora has 5-septate ascospores with an up to 25 µm long tail at the lower end. Pyrenula spissitunicata has a thallus with lichexanthone, fused ascomata with common ostioles covered by thallus and ascospores resembling a Pyrgillus. The lichenicolous fungus Pyrenidium coccineum (parasitic on Siphula decumbens) has red ascomata which stain herbarium boxes blue.

The goal of this paper was to explore trade-offs between fecundity and carbon based secondary metabolites (CBSM) production within the thallus of three species of Rock-shield and Ring lichens, Arctoparmelia centrifuga, Xanthoparmelia viriduloumbrina and X. cumberlandia. Fecundity was measured by numbers of apothecia per thallus, number of spores per apothecium and percent spore germination, and it was compared with the quantity of the major CBSMs produced by the thallus. Results showed negative correlations between stictic acid and all three measures of fecundity for X. cumberlandia, which are consistent with trade-offs. When thallus and apothecium quantities of CBSMs were compared, stictic acid was the only CBSM with levels in the apothecium that were significantly higher than those in the thallus supporting a function that may protect ascospores against herbivory. Other CBSMs are hypothesized to have functions associated with the thallus and UV protection of green algae.

During a revision of the Sematophyllaceae for the Flora of Southern Africa project, we found a new species of Sematophyllum. Aquatic with poorly developed alar region, it is one of the biggest of the genus in southern Africa. It is only known from the Afromontane region and is not particularly threatened inasmuch as it occurs in a number of protected areas. Details of its morphological characters are illustrated and the geographical distribution mapped. A key to the species of Sematophyllum in southern Africa is also provided.