Fruticose lichens often live in environments where airflow and atmospheric water input may influence their morphology. Measurements of the “pendulosity” (erect length/total length) of Usnea and Ramalina thalli growing on tall, cylindrical cacti in a fog-influenced desert show local-scale patterns that fit with aerodynamic theory. Windward thalli were shorter and more erect while leeward thalli were significantly more pendulous, consistent with expectations for the harvesting of water droplets from foggy air.

The fossil liverwort Hepaticites oishii from the Momonoki Formation in Western Honshu, Japan is critically reviewed. The type material exhibits the following characteristics: (1) small thalloid plants with well-defined midrib and lamina; (2) regularly dichotomously branching habit; (3) attenuate apical part of thallus with unnotched apex; (4) lack of ventral scales; (5) undulate lamina and margin of thallus without marginal teeth or hair; and (6) presence of rhizoids on midrib. These characters suggest an affinity of H. oishii to members of simple thalloid liverworts, particularly Pallaviciniales (Jungermanniopsida, Marchantiophyta). The species is therefore assigned to the fossil genus Pallaviciniites with a new combination: Pallaviciniites oishii (Huzioka & Takahasi) T. Katag. This liverwort fossil is significant because it constitutes the first fossil record of the order Pallaviciniales from the Late Triassic of Eurasia and is the second-oldest fossil liverwort in East Asia after Riccardiothallus devonicus from China.

Lichens in the Arctic play important ecological roles. They also face the threats of increasing fire and shrub and tree expansion, exacerbated or caused by climate change. These forces may lead to changes not only in lichen community composition but also in the abundance, diversity and distribution of lichen functional traits. We sought to connect landscape-scale patterns of lichen community composition and traits to environmental gradients to both monitor lichen communities and clarify community-trait-environment relationships. We measured lichens throughout one of the largest and most remote U.S. National Parks within the Arctic. We then analyzed lichen community composition and species richness within ecologically informative lichen trait groups along environmental and vascular vegetation gradients. Macrolichen species richness in 0.4 ha plots averaged 41 species with a total landscape level observed gamma diversity of 262 macrolichen species. Jackknife estimators placed the landscape level macrolichen diversity at 307 to 331 species. A gradient from low-elevation forests to high elevation rocky areas was the dominant ecological gradient as expressed by the lichen community, representing 68% of the variation in species composition. Low-elevation forests hosted more epiphytic lichens characteristic of boreal forests, whereas high-elevation lichen communities were characterized by saxicolous lichens, varying between siliceous, basic or mafic rock types. Along this gradient, species reproducing vegetatively and lichens with filamentous growth form were more frequent in forests while the diversity of traits was highest in alpine habitats. Simple cladoniiform, as opposed to erectly branched fruticose lichens in the genus Cladonia, were the only functional group associated with tussock tundra. Vegetation types differed significantly in lichen species composition and richness and trait richness; characteristic suites of lichen species and traits are associated with the particular vegetation types in the Arctic. We also extended the range of Fuscopannaria abscondita reported new to North America and Zahlbrucknerella calcarea new to Alaska.

Chemical and antioxidant responses of the water-deficit tolerant Chinese liverwort, Plagiochasma appendiculatum, to water-deficit stress were investigated in this study. The results showed that water-deficit stress could increase the accumulation of the main bisbibenzyl, riccardin D (RD), and the level of the expression of genes related to production of RD. Activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), soluble protein and malondialdehyde (MDA) content could be used as indicators of the degree of damage to plants under different water-deficit stresses. Among these indicators, SOD played a significant role in defense against water stress when humidity is higher than 40 ± 5% RH (relative humidity), while the activities of POD and CAT were inhibited. However, when humidity is lower than 40 ± 5% RH, POD and CAT activities were accelerated, and if water-deficit reached serious levels (≤ 20 ± 5% RH), POD activity was inhibited, while CAT activity was long-lasting and enhanced; soluble protein and MDA content exhibited the opposite trend. Below 70 ± 5% RH, MDA contents were the highest among all treatments, suggesting that over-wetting is a significant stress for this liverwort. Content of MDA is higher after one week rather than two weeks, suggesting that the liverwort has the ability to eliminate MDA produced by membrane lipid peroxidation. The results of this study provide optimized soil humidities to improve the production of riccardin D in a cultivated liverwort.

The relationships among species of the epiphytic genus Aptychella (Broth.) Herzog and Clastobryopsis M. Fleisch. were inferred based on phylogenetic analyses of plastid (rpl16, rps4, and trnL-F) and mitochondrial (nad5) gene sequences as well as morphological features. One of the Asian members, Aptychella robusta (M. Fleisch.) M. Fleisch., exhibits much genetic variation and differentiation among populations, which may reflect the presence of cryptic species. The distinctiveness of Asian members characterized by unicostate leaves, A. brevinervis (M. Fleisch.) M. Fleisch., A. pseudobrevinervis H. Akiyama and A. oblongifolia H. Akiyama, are confirmed. On the contrary, Aptychella proligera, the sole member of the genus known from South and Central America, is shown to have a close relationship to the A. brevinervis complex and preserves low genetic variation among samples collected from geographically remote localities. This lack of variation might be caused by a recent immigration from Asian populations. The Asiatic genus Clastobryopsis is treated as a synonym of Aptychella based on the present phylogenetic analyses. One new combination is proposed—Aptychella imbricata (H. Akiyama et al.) H. Akiyama comb. nov.

A second species of the genus Xyleborus, X. nigricans, is described as new to science from the Mid-Atlantic Coastal Plain of eastern North America where it appears to be endemic. The species is illustrated and compared to the allopatric X. sporodochifer, which occurs in the Ozark Highlands and Appalachian Mountains of eastern North America. The northern temperate and Appalachian floristic elements within the Atlantic Coastal Plain are also discussed.

The new species Cora sanctae-helenae Lücking and Cora trindadensis Lücking, M. Cáceres, N.G. Silva & R.J.V. Alves are described from the South Atlantic islands of Saint Helena (British Overseas Territory) and Ilha da Trindade (Brazil). Both are putative endemics for each of the two islands. Cora sanctae-helenae is with certainty known from three independent historic collections from Saint Helena; it has not been encountered in a recent survey and may have become extinct, considering the massive transformation of native vegetation on the island to farmland and eroded areas. In contrast, C. trindadensis was encountered during more recent surveys on Ilha da Trindade. In addition, a lectotype is selected for C. gyrolophia Fr., the only species of Cora known from the Paleotropics, based on a single gathering (two collections) from the Mascarenes (Mauritius). Cora trindadensis, C. sanctae-helenae and C. gyrolophia represent the three easternmost and only extra-American occurrences of Cora, which is otherwise an exclusively neotropical to southern South American genus (including the Galápagos Islands and the Juán Fernández Islands). While the geographic origin of the type material of C. gyrolophia was in some doubt, the phylogenetic relationships of the vascular plant flora of Saint Helena indicate partial affinities with the Neotropics and South America on the one hand and with Africa and the Mascarenes on the other, placing the occurrence of Cora in the South Atlantic and the Mascarenes in a new perspective as a possible eastward expansion of the genus originating from South America.

Atmospheric deposition of sulfur (S) and nitrogen (N) has decreased steadily in the northeastern U.S. since the federal 1970 Clean Air Act was passed, yet deposition remains elevated above natural background levels throughout the region. Epiphytic macrolichens are highly sensitive to air pollution and their status is a good indicator of ecological health. We used deposition modeling for 2000–2013 and multiple metrics of lichen status (i.e., species composition, species richness, thallus condition, lichen sensitivity indices, lichen elemental analysis) to assess air pollution effects at 24 plots in four federally-mandated Class I areas. The areas (Lye Brook Wilderness, VT; Great Gulf and the Presidential Range-Dry River Wildernesses, NH; and Acadia National Park, ME) encompass a range of high to low deposition sites. We developed thallus condition scores and sensitivity groups and indices for S and N based on species patterns using deposition estimates gleaned from a larger, independent data base. Non-metric multidimensional scaling ordinations differentiated forest structure effects on lichen community composition from more complex deposition and elevation effects. Annual mean and cumulative deposition of N correlated strongly with decreases in lichen species richness and N-sensitive species, and poorer thallus condition. Cumulative dry deposition of S yielded the best fit to decreases in thallus condition, poorer community-based S Index values, and absence of many S-sensitive species. Multiple metrics provided consistent evidence that higher depositional loading was associated with greater adverse effects. In general, stronger correlations between present day lichen metrics and cumulative deposition (post-2000), compared to current deposition, emphasize the long-term nature of emissions impacts and continued need to control S and N emissions to restore the ecological health of lichen communities and linked biota.