Genetic markers from horizontal starch gel electrophoresis show clearly that boreal-arctic C. stygium, a bisexual polyploid with n  =  14, is closely related to C. arcticum and C. latifolium, unisexual haploids with n  =  7. One locus of C. stygium shows fixed heterozygosity, suggesting an allopolyploid origin with these two haploids as progenitors. Two other loci, which are heterozygous in >90% of all plants screened, also support this view. It is also possible, however, that C. stygium is an autopolyploid, most likely of C. arcticum, in which meiosis has become regularized. Despite strong morphological differences between them, we detected only one fixed allelic difference between C. arcticum and C. latifolium. For C. subrotundum, another bisexual polyploid with n  =  14, the evidence for allopolyploidy is very strong, with seven fixed heterozygous loci out of 17 scored. One of the lineages involved is similar to that of C. arcticum and C. latifolium, but the other is highly divergent from any known extant species of Cinclidium. It is quite possible, however, that additional, highly divergent species exist or, at least, once existed, as our screening of populations from Alaska turned up a new, highly genetically distinct species that experts have previously mistakenly referred to C. latifolium.

This paper describes a fossil record from northeastern Poland of Sphagnum obtusum Warnst., a plant that has rarely been found in Holocene sediments. This species occurred circa 1710–1570 cal. BP on Mechacz Wielki peatland and was present in the transitional phase between a fen that developed on lake sediments and a bog. Sphagnum obtusum was a dominant species and was accompanied by such vascular plants such as Scheuchzeria palustris, Carex rostrata, Comarum palustre and Oxycoccus palustris. Using testate amoebae, we reconstructed the past habitat (water table and pH), with S. obtusum occurring in a moderately wet habitat (mean depth to the water table or DWT  =  9.5, SD  =  0.5) and under slightly acid conditions (mean pH  =  5, SD  =  0.1). A clear correlation was found between the distributions of the subfossil S. obtusum and those of the indicator testate amoebae Hyalosphenia papilio and Cyclopyxis arcelloides. The disappearance of S. obtusum is assumed to have been caused by a trophic shift and succession of a more acidophilic species, Sphagnum angustifolium.

Three new species, Chaenotheca erkahomattiorum, Chaenothecopsis dibbleandersoniarum and C. marcineae are described from Maine, Nova Scotia, New Brunswick and Quebec, in the Acadian Forest Ecoregion of northeastern North America. In addition, Calicium pinastri and Chaenothecopsis amurensis are reported for the first time in North America, and Calicium adaequatum, Chaenothecopsis asperopoda, C. tsugae, C. ussuriensis, Sclerophora amabilis and S. farinacea are reported as new to eastern North America. Keys for identifying white-pruinose and epruinose species of Chaenotheca in North America, and the species of Chaenothecopsis in the Acadian Forest Ecoregion are also included.

Dimelaena lichenicola is a juvenile parasite on D. oreina and D. thysanota, developing an independent brown areolate lichenized thallus on gneiss and acid rock. It differs from D. californica primarily in producing longer conidia (6.0–10.0 × 1.0 vs. 5.0–6.0 × 1.0 µm), having a reduced thallus and minute lobes, lacking a well-developed plicate margin and a prothallus, having a different host species (D. oreina and D. thrysanota vs. D. radiata), and a different habitat (montane vs. coastal). It is reported from North America (California) and Europe (Italy).

Blindia Bruch & Schimp. is represented in southern South America by eight species. Of these, B. buckii B.K. Andreas, B. rigida B.K. Andreas and B. serrata B.K. Andreas, from the Cape Horn Archipelago, are newly described and illustrated herein. Sporophyte descriptions and the sexuality of B. inundata and B. torrentium are reported for the first time. Species descriptions and a key to species from southern South America are presented.

The North American endemic moss Dicranum howellii Renauld & Cardot, described in 1888 based on material from Oregon, U.S.A., had yet to be validly typified. A lectotype for D. howellii is designated herein based on one of two potential type specimens in the Renauld collection in PC. Dicranum howellii is currently known from western North America in Canada (British Colombia) and the U.S.A (Alaska, California, Idaho, Montana, Oregon and Washington). Traditionally it has been considered as close to, or a synonym of, Dicranum scoparium Hedw. and specimens of it are frequently confused with the latter species. Dicranum howellii can be distinguished from D. scoparium based on its suddenly narrowed inner perichaetial leaves that end in a long, flexuose point; leaves that are concave below and tubulose above; slightly decurrent leaf bases; in transverse section, leaf cell-walls that are of variable thickness; and the presence of a sulcus on the dorsal side of the costa.

Two members of the Lecanora varia group (sensu Eigler), L. strobilina and L. symmicta, can be difficult to distinguish in northeastern North America. Morphological and chemical investigation of 277 specimens recognizes two species in northeastern North America, both fitting European concepts of L. strobilina and L. symmicta. The only reliable character for separating them is the size of the exciple (consistently larger in L. symmicta). Within each of these two species, previously unknown chemical variation is revealed—L. strobilina comprises three distinct chemotypes, while L. symmicta includes two. An isotype of L. symmictera is shown to contain the thiophanic acid chemosyndrome by HPLC, and hence the name L. symmictera cannot be applied to the xanthone-deficient chemotype of L. symmicta. Chemistry is not correlated with morphology or geographic distribution in either L. strobilina or L. symmicta, so we regard the chemotypes of these two species as intraspecific variation.

An extinct moss species Muscites kujiensis is described based on a plant fragment preserved in Late Cretaceous (Santonian, 83–87 Ma) amber from the Kuji district, northern Honshu, Japan. It is characterized by (1) small size of the shoot, less than 5 mm wide, (2) distant leaf arrangement, (3) oblong leaves with a single costa, (4) entire leaf margins without bordered cells, and (5) transparent outer layer of stem. The lack of apical parts of the shoot, reproductive structures and sporophytes prevents us from giving a more extensive comparison of M. kujiensis to extant species, but the characters observed in this species suggest an affinity to Bryopsida. Along with the spore genus Stereisporites (Sphagnaceae) and Polytrichites aichiensis, which is based on transverse sections of a fossilized stem, M. kujiensis is one of the few fossil mosses reported from Japan and the first unequivocal evidence of fossilized moss shoots found in Japan, an important addition to our knowledge of Late Cretaceous mosses from East Asia.

The new species Gyalideopsis ellipsoidea and Pyrenula xanthoglobulifera are described from NE Brazil. These species were found in the Caatinga area reserve Chapada do Araripe, in Ceará. The Pyrenula is also known from Guadeloupe.