Lichen and bryophyte diversity is often exceptional in old rainforests of the temperate zone, but these forests occupy only a very small fraction of their former extent. Epiphyte diversity changes along the vertical gradient of a tree, but in Nova Scotia, Canada, no studies have investigated higher canopy strata, leaving the composition of epiphytes in these habitats uncharacterized. In this study, we explore arboreal lichen and bryophyte communities in the lower crown and lower bole of old eastern hemlock trees. We examined 27 trees at 9 sites across Nova Scotia, Canada. Each tree was surveyed using visual percent-cover estimates at the lower bole and in the lower crown. Single rope ascension was used to access the lower crown with minimal impact on epiphyte communities or tree cambium health. Habitat properties were also recorded, including bark pH, tree girth and height, and canopy cover. Results showed higher pH, and greater richness and cover of macrolichens in the lower crown compared to the lower bole, whereas bryophyte species richness and microlichen cover were both greater on the lower bole of host trees compared to the lower crown. Macrolichen diversity, as represented by Shannon's index (H'), did not differ in relation to habitat, but it increased from the northeast to the southwest of the province. Our results provide a baseline for lichen and bryophyte diversity on old eastern hemlock.

Lecanora exspersa Nyl., a corticolous sterile sorediate crustose lichen previously known only from sparse collections in the mountains of Eurasia, is here reported as new to North America. We collected eight specimens attributable to this name as a part of our recently launched comprehensive lichen inventory of the southern Rocky Mountains and adjacent high plains of Colorado. Chemical and morphological study of these specimens as well as a molecular phylogeny containing our specimens, accessions of L. exspersa from Europe, and other sorediate members of the genus with which L. exspersa may be confused, helped to confirm its identification and placement within the L. subfusca group. This new record for North America is characterized by its thin, grey, smooth to verruculose thallus on bark or wood, its discrete, circular mint-green soralia that erupt from verrucae (these becoming larger and plane with age and often bearing a prominent thalline rim), and its production of atranorin and nephrosteranic acid. We provide discussion along with a dichotomous key to help facilitate the identification of this species and other sorediate species of Lecanora from western North America. Continued fieldwork followed by herbarium studies of the Colorado lichen biota will, we predict, yield many new additional records as in the present report as well as species new to science.

Lichen photomorphs refer to distinct symbiotic structures formed by conspecific fungi associated with different photosynthetic partners, either a green alga or a cyanobacterium. Thus, a single fungal species can engage in symbiotic relationships with different photobionts, resulting in independent, often morphologically distinct, lichen thalli. Historically, the morphological dissimilarity between photomorphs has often led to their classification as separate fungal species, which could even have been accommodated in different genera. However, molecular data have played a crucial role in revealing the genetic similarity and conspecific nature of the fungi composing these photomorphs. In this study, we employed a phylogenetic framework to validate the conspecificity of photomorph pairs within three species indigenous to the Americas: Nephroma kuehnemannii, Ricasolia quercizans and Sticta ainoae. Consequently, Nephroma microphyllum is considered a synonym of N. kuehnemannii, Dendriscocaulon intricatulum a synonym of R. quercizans, and free-living Chilean dendriscocauloid lichens are shown to be cyanomorphs of S. ainoae. A species distribution modeling approach to investigate the geographical distribution and niche characteristics of photomorphs within R. quercizans in eastern North America revealed that its two photomorphs exhibit distinct distributions and ecological niches, suggesting potential adaptations to different environmental conditions. The confirmed conspecificity and niche variation among the considered photomorphs provide insights into the ecological and evolutionary dynamics of these symbiotic associations.

We expanded our knowledge of the Cladonia cariosa group by seeking out and sequencing squamulose epodetiate Cladonia specimens in western North America. Cladonia galindezii, a species in the Cladonia cariosa group with large squamules forming thick mats and often containing porphyrilic acid, as in the type specimen from Antarctica, was found in several western states, new to the United States. In the same clade were specimens with atranorin only or atranorin with norstictic acid. We also establish Cladonia andereggii as another species in the C. cariosa group, from Idaho and Washington, based on sequencing new specimens from near the type locality. Although C. andereggii resembles C. symphycarpa in having norstictic acid-containing medium-sized squamules, ITS sequences of C. andereggii showed that it is more closely related to C. cariosa than to C. symphycarpa. We also demonstrated chemical diversity in the remainder of the C. cariosa group in western North America, with five chemotypes, all with atranorin, most frequently with atranorin only, less frequently with porphyrilic acid, homosekikaic acid, norstictic acid, or fumarprotocetraric acid, some of these in combination with rangiformic acid. While C. andereggii consistently contained norstictic acid and atranorin, C. galindezii and the remainder of C. cariosa s.l. varied in major substances.

Bryoclavula dryalisepiplutea, a new lichenized basidiomycete, is described from Fort Boggy State Park in Leon County, Texas. U.S.A., and represents the second species in the genus outside of Japan, and a first record for a lichenized basidiomycete for Texas. Morphological observations and phylogenetic analyses of the nuclear ITS and nrLSU regions using maximum likelihood and Bayesian analyses supports placement within Bryoclavula (Hydnaceae: Cantharellales), and distinct from the previously described species, B. phycophila, from Japan.

The checklist includes a listing of the genera and species of North American Bryophyta thought to occur in the continental United States and Canada. The floras of Mexico, Hawaii and Greenland are not included. The current list recognizes 1565 species, 12 subspecies, 34 varieties and one form (for a total of 1612 taxa) in 366 genera and 100 families. As a preface to the list, a systematic arrangement of the families and included genera for North America is presented. Many changes from the previous checklist are documented via footnotes that provide references to where changes were made. Only synonymy since the previous checklist is included. Twenty nomenclatural changes are made. These include 19 new combinations: Bryum brassicoides (≡ Gemmabryum brassicoides), B. pacificum (≡ Ptychostomum pacificum), B. torenii (≡ Imbribryum torenii), B. vinosum (≡ Gemmabryum vinosum), Chionoloma maragniphyllum (≡ Oxystegus maragniphyllus), Lescuraea tribulosa (≡ Pseudoleskea tribulosa), Pterygoneurum 3kieneri (≡ P. subsessile var. kieneri Habeeb), Pylaisiadelpha canadensis (≡ Brotherella canadensis), Streblotrichum convolutum var. eustegium (≡ Barbula eustegia), Streblotrichum convolutum var. gallinula (≡ Barbula convoluta var. gallinula), Voitia angustata (≡ Splachnum angustatum), V. mnioides (≡ Splachnum mnioides), V. pallida (≡ Tetraplodon pallidus), V. paradoxa (≡ Splachnum paradoxum), V. urceolata (≡ Splachnum urceolatum), Warnstorfia badia (≡ Hypnum badium), W. straminea (≡ Hypnum stramineum), W. straminea var. patens (Lindb.) (≡ Amblystegium stramineum var. patens), W. wickesiae (≡ Calliergon wickesiae). A new order is also introduced: Rhizogemmales W.R.Buck & Goffinet (≡ Rhizogemmaceae Bonfim Santos, Siebel & Fedosov).