A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution.

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The phylogenetic relationships of liverworts were reconstructed using the sequence data of four genome regions including rbcL, rps4 and trnL-F of the chloroplast and 26S large subunit ribosomal rRNA gene of the nucleus, and 90 characters of morphological, ultrastructural and developmental aspects. The taxa sampled consisted of 159 species including 135 liverworts (108 genera, 54 families and 29 suborders), 13 mosses, two hornworts, seven vascular plants and two charophyte algae. Analyses based on maximum parsimony using both direct optimization (POY) and static alignment (NONA), as well as Bayesian inference (MrBayes) were done. All the data sets were analyzed simultaneously. Our study confirms that liverworts compose a monophyletic group which consists of three classes. The class Treubiopsida including both Treubia and Haplomitrium is resolved as the earliest diverging liverwort lineage. Blasia and the complex thalloids are assigned to the Marchantiopsida, under which Blasiidae and Marchantiidae are divided. Marchantiidae include Sphaerocarpales and Marchantiales. The simple thalloid and leafy liverworts form the Jungermanniopsida, which is further divided to subclasses Pelliidae subclassis nov., Metzgeriidae and Jungermanniidae. Metzgeriidae here is defined to include only Metzgeriaceae, Aneuraceae and Vandiemeniaceae, and is the sister group to the leafy liverworts. The leafy liverworts Jungermanniidae include the orders Pleuroziales, Porellales and Jungermanniales. It is assumed that the Porellales and the Jungermanniales have split early, at least in the Jurassic period. In the Porellales, the diversification rate may have remained relatively constant for long periods of time but speeding up only recently within some of the families, associated with an explosive radiation of angiosperms. The Jungermanniales are most probably a recently diversified group which has attained the greatest profusion of structure and the most remarkable diversity of leaf development and protective devices for maturing sporophytes. A detailed classification scheme for liverworts is presented.

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Bryophytes blanket the floor of temperate rainforests in New Zealand and may influence a number of important ecosystem processes, including carbon cycling. Their contribution to forest floor carbon exchange was determined in a mature, undisturbed podocarp‐broadleaved forest in New Zealand, dominated by 100–400‐year‐old rimu (Dacrydium cupressimum) trees. Eight species of mosses and 13 species of liverworts contributed to the 62% cover of the diverse forest floor community. The bryophyte community developed a relatively thin (depth <30 mm), but dense, canopy that experienced elevated CO2 partial pressures (median 46.6 Pa immediately below the bryophyte canopy) relative to the surrounding air (median 37.6 Pa at 100 mm above the canopy). Light‐saturated rates of net CO2 exchange from 14 microcosms collected from the forest floor were highly variable; the maximum rate of net uptake (bryophyte photosynthesis – whole‐plant respiration) per unit ground area at saturating irradiance was 1.9 μmol m−2 s−1 and in one microcosm, the net rate of CO2 exchange was negative (respiration). CO2 exchange for all microcosms was strongly dependent on water content. The average water content in the microcosms ranged from 1375% when fully saturated to 250% when air‐dried. Reduction in water content across this range resulted in an average decrease of 85% in net CO2 uptake per unit ground area. The results from the microcosms were used in a model to estimate annual carbon exchange for the forest floor. This model incorporated hourly variability in average irradiance reaching the forest floor, water content of the bryophyte layer, and air and soil temperature. The annual net carbon uptake by forest floor bryophytes was 103 g m−2, compared to annual carbon efflux from the forest floor (bryophyte and soil respiration) of −1010 g m−2. To put this in perspective of the magnitude of the components of CO2 exchange for the forest floor, the bryophyte layer reclaimed an amount of CO2 equivalent to only about 10% of forest floor respiration (bryophyte plus soil) or ∼11% of soil respiration. The contribution of forest floor bryophytes to productivity in this temperate rainforest was much smaller than in boreal forests, possibly because of differences in species composition and environmental limitations to photosynthesis. Because of their close dependence on water table depth, the contribution of the bryophyte community to ecosystem CO2 exchange may be highly responsive to rapid changes in climate.

Aim The cosmopolitan genus Herbertus is notorious for having a difficult taxonomy and for the fact that there is limited knowledge of species ranges and relationships. Topologies generated from variable molecular markers are used to discuss biogeographical patterns in Herbertus and to compare them with the geological history of continents and outcomes reported for other land plants.Location Africa, Asia, Azores, Europe, southern South America, northern South America, North America, New Zealand.Methods Phylogenetic analyses of nuclear ribosomal internal transcribed spacer and chloroplast (cp) trnL-trnF sequences of 66 accessions of Herbertus and the outgroup species Triandrophyllum subtrifidum and Mastigophora diclados were used to investigate biogeographical patterns in Herbertus. Areas of putative endemism were defined based on the distribution of species included in the analyses. Maximum parsimony analyses were undertaken to reconstruct ancestral areas and intraspecies migration routes.Results The analyses reveal species-level cladograms with a correlation between genetic variation and the geographical distribution of the related accessions. The southern South American Herbertus runcinatus is sister to the remainder of the genus, which is split into two main clades. One contains the Neotropical-African Herbertus juniperoideus and the New Zealand/Tasmanian Herbertus oldfieldianus. An African accession of H. juniperoideus is nested within Neotropical accessions. The second main clade includes species that inhabit Asia, the Holarctic, Africa, and northern South America. Maximum parsimony analyses indicate that this clade arose in Asia. Herbertus sendtneri originated in Asia and subsequently colonized the Holarctic and northern South America. An Asian origin and colonization into Africa is indicated for H. dicranus. Main conclusionsThe current distribution of Herbertus cannot be explained by Gondwanan vicariance. A more feasible explanation of the range is a combination of short-distance dispersal, rare long-distance dispersal events (especially into regions that faced floral displacements as a result of climatic changes) extinction, recolonization, and diversification. The African Herbertus flora is a mixture of Asian and Neotropical elements. Southern South America harbours an isolated species. The molecular data indicate partial decoupling of molecular and morphological variation in Herbertus. Biogeographical patterns in Herbertus are not dissimilar to those of other groups of bryophytes, but elucidation of the geographical ranges requires a molecular approach. Some patterns could be the Journal of Biogeography (J. Biogeogr.) (2007) 34, 688-698 688

A tree based on DNA sequences from the ITS region of rDNA of New Zealand members of the tribe Gnaphalieae is presented. The tree supports recognition of the genus Anaphalioides. The closest relatives of this genus are other New Zealand gnaphalioid genera: Leucogenes, Raoulia, Ewartia, and species currently assigned to Helichrysum. The tree suggests that there were at least four dispersal events to New Zealand of ancestors to the present gnaphalioid flora. The tree provides information on the relationships of other New Zealand genera in the Gnaphalieae: that Ewartiothamnus (Ewartia sinclairii) is not a sister genus to Ewartia, that Leucogenes is not a sister genus to Leontopodium, and that the New Zealand whipcord Helichrysum species do not belong in Ozothamnus.