The North American, Central American and West Indian species of the lichen genus Haematomma are revised, with special emphasis given to the chemistry and distribution of the taxa. Nineteen species and an additional variety are accepted for the region, including one new species from the West Indies: Haematomma caperaticum. All these taxa are given full descriptions, and a key to their identification is provided. The varieties of H. ochroleucum are regarded as unnamed chemotypes. The presence of fatty acids, including caperatic, rangiformic and bourgeanic acids, are reported for the first time for the genus and are taxonomically important. In addition, two new usnic/placodiolic-type dibenzofuran derivatives (Hgy-1 and Hgy-2) characterize a chemotype of H. guyanense, a common sorediate species known mainly from Florida. This species and H. leprarioides are reported as new to North America. Notes on the chemistry and, in a few cases, the morphology, of 11 non-American species are also provided. Rosellinula kalbii was found growing as a parasite on H. guyanense, the first report on this host.

Arthropod and epiphyte assemblages were compared at three heights (0–2, 2–4 and 4–6 m) on the boles of red maple (Acer rubrum) trees located in a closed canopy forest and within harvest gaps. A positive correlation among bryophytes, Collembola (springtails) and Araneae (spiders) suggested a potential trophic interaction where arboreal spiders, during early developmental stages, were dependent upon availability of Collembolan prey. This relationship appeared to be sensitive to a decline in bryophyte abundance that occurred following gap harvesting. Fifteen families of Diptera (flies) were identified, eight of which were common. The eight common families utilized the arboreal habitat differently depending on height along the bole and abundance of crustose and other lichens. A potential association was identified between six Dipteran families and a Collembolan morphospecies in the family Entomobryidae, suggesting a diverse arthropod community that exploits different attributes of the arboreal habitat and exhibits varied responses to harvest gaps.

Evidence is accumulating that significant amounts of substances can move internally in ectohydric bryophytes, which lack specialized structures for internal water movement. This potential for resource translocation is likely to affect the productivity in individual shoot sections. We tested whether annual growth intervals in the pleurocarpous moss Pseudocalliergon trifarium were performing as independent units by comparing the biomass of annual increments within individual shoots from 13 populations from northern and central Sweden. Pseudocalliergon trifarium has a distinct shoot architecture with discrete annual segments and is therefore well suited to study annual biomass allocation patterns. Mass of the most recent growth interval was directly correlated with segment mass of at least two preceding years. The strength of the relationship between current growth and four consecutively older annual increments decreased linearly with age of the annual segments, suggesting that correlations within shoots were the result of resource translocation rather than of among-year correlations in local environmental factors. Our data suggest that interconnected segments are physiologically integrated, and that size relationships between successive increments are relatively independent of environmental conditions. We conclude that annual growth intervals cannot be considered as independent assimilatory units. Internal resource transfer across annual segments may buffer variation in external availability of or internal demands for resources, and has implications for the understanding of growth patterns and reproductive investments in ectohydric bryophytes.

The interaction between UV radiation and mineral availability has not been investigated in bryophytes, despite the important peculiarities of their mineral nutrition. The question under investigation was whether an improvement in phosphorus (P) availability, and the consequent increase in tissue P concentration, modified the responses to enhanced UV radiation in two aquatic bryophytes (the liverwort Jungermannia exsertifolia subsp. cordifolia and the moss Fontinalis antipyretica) under laboratory conditions. These responses were evaluated in terms of photosynthetic pigment composition, chlorophyll fluorescence, photosynthesis and respiration rates and the accumulation of protecting UV-absorbing compounds (both the commonly used bulk UV-absorbance of methanol extracts in both species and the concentrations of five hydroxycinnamic acid derivatives in the liverwort). The culture period (36 days) affected significantly most variables of both species. However, no variable in either species showed significant differences between the P-supplemented and non-supplemented samples at the end of the experiment, except the vitality index OD₄₃₀/OD₄₁₀ in the liverwort. This was probably due to the fact that the bryophytes studied have low nutritional requirements, and thus increasing tissue P may have only increased luxury consumption, without any modification in the responses to enhanced UV radiation.

The intrathalline heterogeneity of chlorophyll a fluorescence (C_aF) in thalli of the foliose lichen Flavoparmelia caperata was studied measuring F_o, F_m, F_v/F_m, ΔF/F_m′, NPQ and F_t in two spots of 25 mm² positioned at ca 0.8 and 3 cm from the thallus margin. Measurements were carried out both in the field and in the laboratory using north-exposed, epiphytic thalli occurring in a deciduous wood of the Karst plateau (Trieste, NE Italy). With the exception of NPQ, all parameters were statistically higher in the marginal spots than in the central ones, suggesting that the level of photochemical activity is higher where the photobiont cells are more dense and younger. F_m and F_v/F_m of marginal spots measured in the field were statistically lower than those measured in the laboratory, probably as a consequence of the different pre-treatment conditions. The importance of selecting a specific measuring spot, particularly for biomonitoring purposes, is discussed.

A new moss species from northern California, Grimmia torenii Hastings, is described. The species is gametophytically similar to Grimmia ovalis, but sporophytically resembles Grimmia tergestina. Many specimens of Grimmia torenii have leaves with papillate-mammillae, readily separating the species from both G. ovalis and G. tergestina. Similar to G. tergestina the perichaetial leaves are enlarged, broadly lingulate and almost entirely filmy throughout. However, these leaves are abruptly narrowed distally to a subulate apex and the distal laminal cells are distinctly thicker than in G. tergestina. Unlike G. tergestina, the peristome is composed of disarticulated teeth and these are often fused at the base; further, the operculum has bulging cells. Grimmia tergestina is rejected from North America; all reported specimens are either G. ovalis, G. poecilostoma or G. torenii.

A new species, Drepanolejeunea longifolia, from the rain forest of Meghalaya province in eastern Himalayas has been investigated and is described as new. It is confined to the Mawphlong Forest and Elephant Falls in East Khasi Hills of Meghalaya and differentiated from the similar D. angustifolia by larger (20 mm) plants; erect, distant, triangular leaves with entire margins and lack of ocelli. Some variable morphoforms of D. erecta exhibiting small plants, suboblique, oblong to sub-elleptical, more or less entire leaves (rarely with 2–3 marginal protrusions in young leaves) with single-celled leaf ocelli and 5-keeled perianth have also been encountered and are described here.

A total of two varieties, two subspecies and 67 species distributed among 41 genera and 23 families of hepatics and hornworts are recorded for the department of Nariño; 58 species, two subspecies and two varieties represent new additions. One species is newly recorded for Colombia: Calypogeia venezuelana. Eleven species and one subspecies are also recorded for the department of Putumayo, nine species and one subspecies representing new records.

A new foliicolous lichen species, Enterographa oregonensis (Ascomycota: Arthoniales: Roccellaceae) is described from temperate coastal North America. It differs from similar, tropical species in its combination of 5(–7)-septate spores, a gelatinous perispore, short lirellae and presence of gyrophoric acid. The ecology of this species is discussed and a conservation assessment is recommended.

Fissidens tumescens is described and illustrated from Dominica and Guadeloupe in the eastern Caribbean Sea. The species belongs to subgenus Aloma, and is most similar to F. neglectus. Its distinctive features include: slender leafy stems; intralaminal, unistratose limbidia that extend to about ½–¾ the length of the vaginant laminae of most leaves; smooth, tumid laminal cells that vary from unistratose to bistratose; and, marginal laminal cells often papillose on the margins.

Pyramidula tetragona (Brid.) Brid. is reported for the first time from Turkey. The species is described from material collected on wet soil in an archaeological site (Tilmen Höyük) in southeastern Anatolia.

Chenia ruigtevleia is described from two localities in the Western Cape Province of South Africa. It is most readily distinguished from congeners by the presence of laminal papillae. Further points of distinction from the apparently closely related C. leptophyllum are the smaller laminal cells and generally short-ovate leaves. We provide a key for the four species recognized in Chenia.

Symphysodontella siamensis Dixon (Pterobryaceae), previously known only from Thailand, is reported here as the first record of the genus to the moss flora of China. A description and illustrations based on the Chinese material are provided.

Macromitrium hainanense is described and illustrated as a new species from the Hainan Province of China. This species, belonging to a gymnostomous group of Macromitrium, is most closely related to M. taiheizanense from Taiwan. It is distinguished from all congeners by the immersed and ovoid capsules with exceedingly short setae (ca. 0.2–0.4 mm long), the absence of a peristome, the rounded-quadrate to oblate, pluripapillose upper laminal cells, the elongate and sigmoid-curved, smooth basal cells and the hairy, campanulate-mitrate calyptrae.

The new genus Angiactis Aptroot & Sparrius is described, with three species, A. bermudensis LaGreca sp. nov. from Bermuda, A. littoralis (Kantvilas) Aptroot & Sparrius comb. nov. from Australia and A. spinicola Aptroot & Sparrius sp. nov. from the Galápagos. The new genus differs from Lecanographa in the presence of a thalline exciple, and from Llimonaea in the non-corticate thallus and presence of a thalline exciple.