William R. Buck

PHYLOGENETIC EVIDENCE OF A RAPID RADIATION OF PLEUROCARPOUS MOSSES (BRYOPHYTA)

Abstract Pleurocarpous mosses, characterized by lateral female gametangia and highly branched, interwoven stems, comprise three orders and some 5000 species, or almost half of all moss diversity. Recent phylogenetic analyses resolve the Ptychomniales as sister to the Hypnales plus Hookeriales. Species richness is highly asymmetric with approximately 100 Ptychomniales, 750 Hookeriales, and 4400 Hypnales. Chloroplast DNA (cpDNA) sequences were obtained to compare partitioning of molecular diversity among the orders with estimates of species richness, and to test the hypothesis that either the Hookeriales or Hypnales underwent a period (or periods) of exceptionally rapid diversification. Levels of biodiversity were quantified using explicitly historical “phylogenetic diversity” and non‐historical estimates of standing sequence diversity. Diversification rates were visualized using lineage‐through‐time (LTT) plots, and statistical tests of alternative diversification models were performed using the methods of Paradis (1997). The effects of incomplete sampling on the shape of LTT plots and performance of statistical tests were investigated using simulated phylogenies with incomplete sampling. Despite a much larger number of accepted species, the Hypnales contain lower levels of (cpDNA) biodiversity than their sister group, the Hookeriales, based on all molecular measures. Simulations confirm previous results that incomplete sampling yields diversification patterns that appear to reflect a decreasing rate through time, even when the true phylogenies were simulated with constant rates. Comparisons between simulated results and empirical data indicate that a constant rate of diversification cannot be rejected for the Hookeriales. The Hypnales, however, appear to have undergone a period of exceptionally rapid diversification for the earliest 20% of their history.

Changing lenses to assess biodiversity: patterns of species richness in sub-Antarctic plants and implications for global conservation

Article discussing patterns of species richness in sub-Antarctic plants and implications for global conservation.

Ordinal Phylogeny within the Hypnobryalean Pleurocarpous Mosses Inferred from Cladistic Analyses of Three Chloroplast DNA Sequence Data Sets: trnL-F, rps4, and rbcL

Abstract Classification of families of hypnobryalean mosses into the Hypnales, Leucodontales, and Hookeriales has been taxonomically difficult. Several researchers have sequenced different genes for independent phylogenetic studies of these three pleurocarp groups. Our goal is to summarize available molecular data and compile the largest data set to infer phylogenetic relationships among families as basis for classification at ordinal level. Sequences of rbcL, trnL-F, and rps4 loci for 38 exemplars of most families of Hypnales, Leucodontales, and Hookeriales were analyzed to evaluate whether or not each of the three orders is monophyletic. Cladistic analyses of combined sequences, using five taxa in the Bryales as outgroups, reveal a robust clade (decay > 5) including all hypnobryalean pleurocarps. Within this group, one clade (decay = 2) includes only taxa of the Hookeriales, and is sister to a large monophyletic group (Hypnales sensu lato) containing all other taxa (decay = 2) previously in the Leucodontales and Hypnales. These relationships suggest that the ordinal level taxonomy needs to be reconsidered since major lineages detected do not correspond to the traditional Leucodontales or Hypnales. These two orders are not supported by any molecular evidence from rbcL, trnL-F, or rps4, either analyzed singly or in different combinations. Additionally, present results indicate the need for changes to the current system of three suborders of Hypnales and four of the Leucodontales. Phylogenetic reconstructions based on molecular data emphasize the need for a re-examination of the taxonomic relevance of morphological characters and corroborate previous interpretations of sporophytic morphological similarities as multiple transitions to similar solutions to epiphytism among the pleurocarps.

Newly resolved relationships in an early land plant lineage: Bryophyta class Sphagnopsida (peat mosses)

UNLABELLED PREMISE OF THE STUDY The Sphagnopsida, an early-diverging lineage of mosses (phylum Bryophyta), are morphologically and ecologically unique and have profound impacts on global climate. The Sphagnopsida are currently classified in two genera, Sphagnum (peat mosses) with some 350-500 species and Ambuchanania with one species. An analysis of phylogenetic relationships among species and genera in the Sphagnopsida were conducted to resolve major lineages and relationships among species within the Sphagnopsida. • METHODS Phylogenetic analyses of nucleotide sequences from the nuclear, plastid, and mitochondrial genomes (11 704 nucleotides total) were conducted and analyzed using maximum likelihood and Bayesian inference employing seven different substitution models of varying complexity. • KEY RESULTS Phylogenetic analyses resolved three lineages within the Sphagnopsida: (1) Sphagnum sericeum, (2) S. inretortum plus Ambuchanania leucobryoides, and (3) all remaining species of Sphagnum. Sister group relationships among these three clades could not be resolved, but the phylogenetic results indicate that the highly divergent morphology of A. leucobryoides is derived within the Sphagnopsida rather than plesiomorphic. A new classification is proposed for class Sphagnopsida, with one order (Sphagnales), three families, and four genera. • CONCLUSIONS The Sphagnopsida are an old lineage within the phylum Bryophyta, but the extant species of Sphagnum represent a relatively recent radiation. It is likely that additional species critical to understanding the evolution of peat mosses await discovery, especially in the southern hemisphere.

Ordinal relationships of pleurocarpous mosses, with special emphasis on the Hookeriales

Abstract Sequence data from four DNA regions, namely, chloroplast trnL‐trnF and rps4, mitochondrial nad5, and nuclear 26S rDNA, were surveyed from 89 taxa traditionally associated with the Hookeriales, five Hypnales and five outgroups. Phylogenetic reconstruction was performed using the maximum parsimony and maximum likelihood optimality criteria and by Bayesian phylogenetic inference. Thirteen morphological characters were optimized on the resulting phylogeny using maximum likelihood. Inferences of character evolution based on the molecular phylogeny suggest that (1) the core of pleurocarpous mosses (i.e. the Hypnanae) is best defined and thus distinguished from the Ptychomnianae by smooth rather than furrowed capsules, (2) a synapomorphy for the Ptychomnianae is the short and double (or absent) costa and (3) the Hookeriales are defined by undifferentiated alar cells. The Ptychomniaceae plus Garovagliaceae are recognized as a single family in its own order, the Ptychomniales ord. nov. and superorder, the Ptychomnianae, superord. nov. This superorder is sister to the combined Hypnales and Hookeriales, i.e. the Hypnanae. The Hookeriales are interpreted as consisting of seven families, the Hypopterygiaceae, Saulomataceae fam. nov., Daltoniaceae, Schimperobryaceae fam. nov., Hookeriaceae, Leucomiaceae and Pilotrichaceae. The Adelotheciaceae are embedded within the Daltoniaceae and considered synonymous with that family. Within the Ptychomniaceae, Ptychomniella is raised from a subgenus of Ptychomnion to generic status. Euptychium setigerum and its monospecific section, Crassisubulata, are transferred to Garovaglia. Callicostella diatomophila is transferred to Diploneuron. Additional alterations at the generic level await more data.

The genus Racomitrium (Grimmiaceae) in Brazil, with the first report of R. subsecundum in South America

Four species of the moss genusRacomitrium Brid. are reported from Brazil:R. subsecundum (Harv.) Wils,R. didymum (Mont.) Lorentz,R. crispipilum (Taylor) A. Jaeger, andR. visnadiae W. R. Buck.Racomitrium subsecundum is reported for the first time from South America in Brazil and Colombia. The species is fully described and illustrated.Racomitrium didymum is recorded for the first time from Brazil; the specimens previously assigned toR. crispulum (Hook.f. & Wils.) Hook.f. & Wils. represent this species.Racomitrium cucullatifolium Hampe andR. crispulum (Hook. f. & Wils.) Hook.f. & Wils. are excluded from the Brazilian bryophyte flora. All Brazilian species ofRacomitrium are briefly assessed taxonomically and bryogeographically and illustrated, and a key to their determination is given. A lectotype is selected forGrimmia didyma Mont.

Taxonomic and nomenclatural rearrangement in the Hookeriales with notes on West Indian taxa

The Hookeriales are evaluated to discern familial limits. Five families are recognized in the order: Hookeriaceae, Leucomiaceae, Daltoniaceae, Callicostaceae, and Adelotheciaceae fam. nov. Chaetomitrium Dozy & Molk., Chaetomitriopsis. Fleisch., Dimorphocladon Dix., and Elharveya Crum are transferred to the Hypnaceae. Hookeriopsis (Besch.) Jaeg. is split into four genera: Hookeriopsis s. str., Brymela Crosby & Allen, Thamniopsis (Mitt.) Fleisch., and Trachyxiphium Buck, gen. nov. The following new combinations are proposed to coincide with the recognition of these four genera rather than Hookeriopsis s. lat.: Brymela acuminata, B. callicostelloides, B. cuspidata, B. fissidentoides, B. fluminensis, B. obtusifolia, B. parkeriana, B. rugulosa, B. websteri, Thamniopsis cheiloneura, T. cruegeriana, T. diffusa, T. incurva, T. langsdorffii, T. pappeana, T. purpureophylla, T. secunda, T. sinuata, T. terrestris, T. undata, T. utacamundiana, T. versicolor, Trachyxiphium aduncum, T. guadalupense, T. heteroicum, T. hypnaceum, T. pernutans, T. subfalcatum, T. tenue, T. vagum, and T. variable. Excluded species are treated as Isopterygium plumicaule, Schizomitrium cirrhosum, and S. subsecundum. Schizomitrium belangerianum (Besch.) Buck, comb. nov. is considered distinct from S. depressum (Hedw.) Buck & Steere, and S. pallidum (Hornsch.) Crum & Anders. is shown to have a smooth seta sometimes. The taxonomy of the aquatic species of Cyclodictyon Mitt. and Lepidopilum (Brid.) Brid. is clarified, resulting in the recognition of three species, Cyclodictyon subtortifolium (Bartr.) Buck, comb. nov., C. roridum (Hampe) Kuntze and L. tortifolium Mitt. Two new combinations are proposed in Calyptrochaeta Desv., C. setigera and C. albescens.

Fire adaptation in Neblinaria celiae (Theaceae), a high-elevation rosette shrub endemic to a wet equatorial tepui

SummaryNeblinaria celiae (Theaceae), a rosette shrub endemic to the exceedingly rainy summit of remote Cerro de la Neblina in southern Venezuela, has a previously undescribed set of adaptations to fire. Its growth form entails sparse branching, massive terminal leaf rosettes, and thick bark. It is highly fire-tolerant, with a survival rate of 93% in a stand recently ignited by lightning, vs. 0% in seven co-occurring woody species. Survival increases sharply with rosette height, favoring a sparsely branched habit that would maximize the rate of upward growth through the sparse fuel layer supported by a sterile substrate. Thick bark and massive rosettes help protect cambial and foliar meristems from brief exposure to high temperatures. Rosettes on shorter plants are exposed to greater damage from fire near the ground and, as expected, are bigger and impound more rainwater; the greater number of leaves nearly balances the greater leaf mortality caused by fire. We relate Neblinarias growth form to its dominance atop Neblina, to a general model for the evolution of sparse branching, and to the evolution of growth form in other tepui plants.

Trachyphyllum, a moss genus new to South America with notes on African-South American bryogeography

Summary Trachyphyllum is reported as new for South America from several Brazilian collections of T. dusenii. African-South American disjuncts in the Bryophyta are discussed and placed into three categories: lowland-lower montane taxa, montane to paramo/elfin forest taxa, and austral-temperate and/or antipodal taxa. Examples of each are given.

Disentangling knots of rapid evolution: origin and diversification of the moss order Hypnales

Abstract The Hypnales are the largest order of mosses comprising approximately 4200 species. Phylogenetic reconstruction within the group has proven to be difficult due to rapid radiation at an early stage of evolution and, consequently, relationships among clades have remained poorly resolved. We compiled data from four sequence regions, namely, nuclear ITS1–5·8S–ITS2, plastid trnL–F and rps4, and mitochondrial nad5, for 122 hypnalean species and 34 species from closely related groups. Tree topologies from both Bayesian and parsimony analyses resolve the order as monophyletic. Although inferences were made from fast-evolving genes, and despite strong phylogenetic signal in the nuclear ITS1–5·8S–ITS2 data, monophyly, as well as backbone nodes within the Hypnales, remains rather poorly supported except under Bayesian inferences. Ancestral distribution based on Bayesian dispersal-vicariance analysis supports a Gondwanan origin of the Hypnales and subsequent geographical radiation in the area of the former Laurasian supercontinent. Reconstruction of historical biogeography is congruent with mainly tropical and Gondwanan distributions in the sister groups Hypnodendrales, Ptychomniales, and Hookeriales, and with the dating for the oldest pleurocarp and hypnalean fossils. We contrast groupings in the phylogenetic tree with recent classifications and other phylogenetic inferences based on molecular data, and summarise current knowledge on the evolutionary history of, and relationships among, the Hypnales.