World checklist of hornworts and liverworts.

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.

The resurrection of Neohattoria Kamim. (Jubulaceae, Marchantiophyta): a six decade systematic conflict resolved through a molecular perspective.

The systematic placement of Frullaniaherzogii has been contentious since its description six decades ago. Over the years it has been interpreted as either a member of the genus Frullania or segregated into its own genus, Neohattoria, due to morphological similarities with both Frullania and Jubula. Here we provide molecular evidence that supports the recognition of the genus Neohattoria and its inclusion within the Jubulaceae, together with Jubula and Nipponolejeunea. Jubulaceae are placed sister to Lejeuneaceae rather than to the monogeneric Frullaniaceae.

Taxonomic novelties in Scapania.

Five new supraspecific taxa of Scapania are proposed, Scapania subg. Gracilidae, Scapania subg. Pseudomacrodiplophyllum, Scapania sect. Americanae, Scapania sect. Hyperboreae, and Scapania sect. Simmonsia.

Frullania knightbridgei, a new liverwort (Frullaniaceae, Marchantiophyta) species from the deep south of Aotearoa-New Zealand based on an integrated evidence-based approach.

Frullania is a large and taxonomically complex genus. A new liverwort species, Frullania knightbridgeisp. nov. from southern New Zealand, is described and illustrated. The new species, and its placement in Frullania subg. Microfrullania, is based on an integrated evidence-based approach derived from morphology, ecology, experimental growth studies of plasticity, as well as sequence data. Diagnostic characters associated with the leaf and lobule cell-wall anatomy, oil bodies, and spore ultra-structure distinguish it from all other New Zealand species of Frullania. A critical comparison is also made between Frullania knightbridgei and morphologically allied species of botanical regions outside the New Zealand region and an artificial key is provided. The new species is similar to some forms of the widespread Australasian species, Frullania rostrata, but has unique characters associated with the lobule and oil bodies. Frullania knightbridgei is remarkably interesting in comparison with the majority of Frullania species, and indeed liverworts in general, in that it is at least partially halotolerant. Maximum parsimony and maximum likelihood analyses of nuclear ribosomal ITS2 and plastidic trnL-trnF sequences from purported related speciesconfirms its independent taxonomic status and corroborates its placement within Frullania subg. Microfrullania.

A phylogeny of the northern temperate leafy liverwort genus Scapania (Scapaniaceae, Jungermanniales).

Scapania is a northern temperate genus with a few disjunctions in the south. Despite receiving considerable attention, the supraspecific classification of this genus remains unsatisfactorily solved. We use three molecular markers (nrITS, cpDNA trnL-F region, atpB-rbcL spacer) and 175 accessions belonging to 50 species (plus eight outgroup taxa) to estimate the phylogeny and to test current classification systems. Our data support the classification of Scapania into six rather than three subgenera, rearrangements within numerous sections, and inclusion of Macrodiplophyllum microdontum. Scapania species with a plicate perianth form three early diverging lineages; the most speciose subgenus, Scapania s.str., represents a derived clade. Most morphological species concepts are supported by the molecular topologies but classification of sect. Curtae requires further study. Southern lineages are nested in northern hemispheric clades. Palearctic-Nearctic distribution ranges are supported for several species.

One species or at least eight? Delimitation and distribution of Frullania tamarisci (L.) Dumort. s. l. (Jungermanniopsida, Porellales) inferred from nuclear and chloroplast DNA markers.

Frullania tamarisci is usually regarded as a polymorphic, holarctic-Asian liverwort species with four allopatric subspecies [subsp. asagrayana, moniliata, nisquallensis and tamarisci]. This hypothesis is examined using a dataset including sequences of the nuclear internal transcribed spacer region and the plastid trnL-trnF and atpB-rbcL regions of 88 accessions of F. tamarisci and putatively related taxa. Maximum parsimony and maximum likelihood analyses indicate the presence of at least eight main lineages within F. tamarisci s. l. The long branches leading to the tip nodes of the different F. tamarisci s. l. clades and their partly sympatric distribution reinforce species rank. Within F. tamarisci s. l. we recognize the Asian F. moniliata, the western North American F. californica and F. nisquallensis, the eastern North American F. asagrayana, the eastern North American-European F. tamarisci s. str., the Macaronesian F. sergiae, and two newly identified European lineages assigned to as F. calcarifera and F. tamarisci var. azorica. The considerable sequence differences are not reflected in conspicuous morphological disparities, rendering F. tamarisci s. l. the most explicit example of a complex of semi-cryptic and cryptic liverwort species. The temperate Frullania clades of this study likely went through recent extinction and expansion processes as indicated by the bottleneck pattern of genetic diversity. Species from tropical regions or regions with an Atlantic climate usually contain several geographical lineages. Our findings support frequent short-distance migration, rare successful long-distance dispersal events, extinction and recolonization as an explanation for the range formation in these Frullania species.

A phylogeny of Adelanthaceae (Jungermanniales, Marchantiophyta) based on nuclear and chloroplast DNA markers, with comments on classification, cryptic speciation and biogeography.

Adelanthaceae (including Jamesoniellaceae) represent a major lineage of jungermannialean liverworts that is characterized by ventral-intercalary, often flagelliform branches, succubous leaves, ovoid to cylindrical, plicate perianths with a contracted mouth, often connate bracts and bracteoles, and 4-7 stratose capsule walls. Here we present the first comprehensive molecular phylogeny of Adelanthaceae using five markers (rbcL, psbA, trnL-trnF region, atpB-rbcL spacer, nrITS1-5.8S-ITS2) and 108 accessions from throughout the geographic range of the family. The molecular data support the separation of subfamilies Adelanthoideae and Jamesonielloideae. The Adelanthoideae include the genera Adelanthus, Pseudomarsupidium and Wettsteinia. The Jamesonielloideae include representatives of the genera Anomacaulis, Cryptochila, Cuspidatula, Jamesoniella, and Syzygiella in five main clades. The monophyly of taxa in current morphological classification schemes of Jamesonielloideae is not supported by the molecular data. Based on the outcome of the molecular phylogenetic analyses we propose to include Anomacaulis and Jamesoniella kirkii in Cuspidatula, and to place Cryptochila, Roivainenia, and Jamesoniella in the synonymy of Syzygiella. Molecular data support intercontinental ranges for several species and a range formation of Adelanthaceae by frequent short-distance dispersal, rare long-distance dispersal, extinction, and diversification. Disjunct distribution patterns within the Adelanthaceae cannot be explained by Gondwanan vicariance.

Morphologically cryptic biological species within the liverwort Frullania asagrayana.

PREMISE OF THE STUDY: The Frullania tamarisci complex includes eight Holarctic liverwort species. One of these, F. asagrayana, is distributed broadly throughout eastern North America from Canada to the Gulf Coast. Preliminary genetic data suggested that the species includes two groups of populations. This study was designed to test whether the two groups are reproductively isolated biological species. • METHODS: Eighty-eight samples from across the range of F. asagrayana, plus 73 samples from one population, were genotyped for 13 microsatellite loci. Sequences for two plastid loci and nrITS were obtained from 13 accessions. Genetic data were analyzed using coalescent models and Bayesian inference. • KEY RESULTS: Frullania asagrayana is sequence-invariant at the two plastid loci and ITS2, but two clear groups were resolved by microsatellites. The two groups are largely reproductively isolated, but there is a low level of gene flow from the southern to the northern group. No gene flow was detected in the other direction. A local population was heterogeneous but displayed strong genetic structure. • CONCLUSIONS: The genetic structure of F. asagrayana in eastern North America reflects morphologically cryptic differentiation between reproductively isolated groups of populations, near-panmixis within groups, and clonal propagation at local scales. Reproductive isolation between groups that are invariant at the level of nucleotide sequences shows that caution must be exercised in making taxonomic and evolutionary inferences from reciprocal monophyly (or lack thereof) between putative species.

DNA taxonomy, cryptic speciation and diversification of the Neotropical-African liverwort, Marchesinia brachiata (Lejeuneaceae, Porellales).

The Neotropical-African liverwort Marchesinia brachiata has long been regarded as a polymorphic species. This hypothesis is examined using a dataset including sequences of the nuclear internal transcribed spacer region and the plastidic trnL-trnF region of 39 Marchesinia accessions. Maximum parsimony, maximum likelihood and Bayesian analyses indicate that Marchesinia robusta is nested within M. brachiata s.l. The molecular topologies support at least three partly sympatric biological species within M. brachiata s.l., the Neotropical M. bongardiana and M. languida, and the Neotropical-African M. brachiata s.s. These species are incompletely separated by subtle differences in underleaf shape and leaf dentation. Long branches within M. brachiata s.s. suggest ongoing speciation processes that are not yet reflected in distinguishable morphological variation. Divergence time estimates based on nrITS sequence variation and the liverwort fossil record indicate an establishment of the species M. bongardiana, M. brachiata, M. languida, M. madagassa, and M. robusta in the Late Oligocene and Miocene. The intraspecific diversity shows distinctive patterns with evidence for constant accumulation of genetic diversity in M. robusta and M. brachiata whereas M. bongardiana and M. languida likely went through a recent extinction or expansion process as indicated by the bottleneck pattern of genetic diversity. The tropical American-African disjunction of M. brachiata is the result of dispersal rather than Western Gondwanan vicariance.

Molecular insights into the phylogeny and subgeneric classification of Frullania Raddi (Frullaniaceae, Porellales).

With an estimated 300-375 species, Frullania is the largest genus of Porellales and forms a major clade of leafy liverworts. The cosmopolitan genus includes mostly epiphytes and represents an important component of the cryptogamic vegetation in various, especially tropical, habitats. There have been abundant changes and modifications to the infrageneric classification of Frullania, with up to fifteen subgenera and numerous sections solely based on morphology. Here we present the first molecular phylogeny of Frullania using four markers (rbcL, psbA, trnL-trnF region of cp DNA, nr5.8S-ITS-2 region) and 171 accessions from throughout the range. The molecular data provide evidence for the monophyly of several subgenera and support intercontinental ranges of these clades. Previous subgeneric assignment for a suite of taxa based on morphological evidence is not supported by the molecular data. Representatives of the genera Amphijubula, Neohattoria and Schusterella are nested in robust subclades of Frullania. Basal relationships within Frullania are largely unsupported. Based on the outcome of the phylogenetic analyses we present a revised supraspecific classification and provide evidence for the monophyly of some morphological species. Disjunct distributional patterns within Frullania cannot be explained by Gondwanan vicariance.

Steady diversification of derived liverworts under Tertiary climatic fluctuations.

Tropical forests contain the majority of extant plant diversity and their role as a cradle and/or museum of biodiversity is an important issue in our attempts to assess the long-term consequences of global climate change for terrestrial biomes. Highly diverse groups of liverworts are an often ignored but extremely common element in rainforests, and thus their evolution may shed light on the ecological robustness of rainforest biomes to climate fluctuations. We record a remarkable constant accumulation of diversity through time for the most species-rich family of liverworts, Lejeuneaceae, inferred by divergence time estimates. The observed pattern supports the recently developed concept of a dual role of the tropics as both a museum and a cradle of biodiversity.

A phylogeny of Porella (Porellaceae, Jungermanniopsida) based on nuclear and chloroplast DNA sequences.

The cosmopolitan family Porellaceae includes about 60 species in two or three genera: the large genus Porella and the monospecific Ascidiota and Macvicaria (alternatively Porella subg. Macvicaria). Maximum parsimony, maximum likelihood and Bayesian inference of phylogeny of a dataset including three markers (rbcL, trnL-trnF region of cp DNA, nrITS region) of 96 accessions resulted in similar topologies supporting the generic status of Ascidiota. Macvicaria is nested in a subclade of Porella. Relationships among species of Porella are in general well resolved and many terminal nodes achieve good statistical support whereas basal relationships are at best moderately supported. Multiple accessions of single species are usually placed in monophyletic lineages. Accessions of P. platyphylla split into a European and a North American clade with one accession from North America embedded within the European samples. The Macaronesian endemic P. inaequalis is closely related to the Asian species P. grandiloba. Porella obtusata and P. canariensis cannot be separated on the basis of the sequence data presented in this study. The molecular topologies indicate a range extension of the Asian P. gracillima subsp. urogea to Eastern North America and of the Neotropical P. swartziana to South Africa. Current supraspecific classifications of Porella are not reflected in the molecular topologies with a correlation between genetic variation and the geographical distribution of the related accessions rather than a correlation between genetic variation and morphology.