Thysananthus ciliaris (Lejeuneaceae, Marchantiophyta): a new record of Thysananthus species for Thailand

Thysananthus ciliaris (Sande Lac.) Sukkharak, a rare species from Sumatra and Peninsular Malaysia, was newly discovered in lowland evergreen forest, southern Thailand. A detailed description and illustrations are here provided

Phaeoceros perpusillus var. scabrellus (Notothyladaceae, Anthocerotophyta), a new taxon from northern Thailand

A new variety of hornwort from northern Thailand, Phaeoceros perpusillus var. scabrellus is described based on morphological characters and molecular phylogenetic analyses. In this study, phylogenetic analyses supported that the new variety is closely related to P. perpusillus var. perpusillus. Morphologically, it is distinguished from the autonimic variety in nearly smooth spores under light microscope. A taxonomic description, illustrations, and light and scanning electron micrographs are provided. In addition, the new variety is assessed as Endangered (EN), demonstrating its rarity by being currently known from only three subpopulations

Liverworts show a globally consistent mid‐elevation richness peak

The study of elevational gradients allows to draw conclusions on the factors and mechanisms determining patterns in species richness distribution. Several earlier studies investigated liverwort diversity on single or few elevational transects. However, a comprehensive survey of the elevational distribution patterns of liverwort richness and their underlying factors is lacking so far. This study's purpose was to fill this gap by compiling an extensive data set of liverwort elevational patterns encompassing a broad diversity of mountains and mountain ranges around the world. Using polynomial regression analyses, we found a prevalence of hump‐shaped richness patterns (19 of 25 gradients), where liverwort species richness peaked at mid‐elevation and decreased towards both ends of the gradient. Against our expectation and unlike in other plant groups, in liverworts, this pattern also applies to elevational gradients at mid‐latitudes in temperate climates. Indeed, relative elevation, calculated as the percentage of the elevational range potentially inhabited by liverworts, was the most powerful predictor for the distribution of liverwort species richness. We conclude from these results that the admixture of low‐ and high‐elevation liverwort floras, in combination with steep ecological gradients, leads to a mid‐elevation floristic turnover shaping elevational patterns of liverwort diversity. Our analyses further detected significant effects of climatic variables (temperature of the warmest month, potential evapotranspiration, and precipitation of the warmest month) in explaining elevational liverwort richness patterns. This indicates that montane liverwort diversity is restricted by high temperatures and subsequent low water availability especially towards lower elevations, which presumably will lead to serious effects by temperature shifts associated with global warming

Comparative analysis of plastid genomes in the non-photosynthetic genus Thismia reveals ongoing gene set reduction

Heterotrophic plants provide intriguing examples of reductive evolution. This is especially evident in the reduction of their plastid genomes, which can potentially proceed toward complete genome loss. Several milestones at the beginning of this path of degradation have been described; however, little is known about the latest stages of plastome reduction. Here we analyze a diversity of plastid genomes in a set of closely related non-photosynthetic plants. We demonstrate how a gradual loss of genes shapes the miniaturized plastomes of these plants. The subject of our study, the genus Thismia, represents the mycoheterotrophic monocot family Thismiaceae, a group that may have experienced a very ancient (60–80 mya) transition to heterotrophy. In all 18 species examined, the plastome is reduced to 14–18 kb and is highly AT-biased. The most complete observed gene set includes accD, seven ribosomal protein genes, three rRNA, and two tRNA genes. Different clades of Thismia have undergone further gene loss (complete absence or pseudogenization) compared to this set: in particular, we report two independent losses of rps2 and rps18

Aphyllorchis periactinantha (Orchidaceae, Neottieae), a new mycoheterotrophic species from peninsular Thailand

A new orchid species from southern Thailand, Aphyllorchis periactinantha, is described and illustrated. The novelty is characterized by the subactinomophic flowers, the concave labellum, not divided into hypochile and epichile, the reduced staminodes, the shallowly bilobed stigma and the semicircular rostellum. A key to the species of Aphyllorchis in Thailand is updated

Aphyllorchis periactinantha (Orchidaceae, Neottieae), a new mycoheterotrophic species from peninsular Thailand

A new orchid species from southern Thailand, Aphyllorchis periactinantha, is described and illustrated. The novelty is characterized by the subactinomophic flowers, the concave labellum, not divided into hypochile and epichile, the reduced staminodes, the shallowly bilobed stigma and the semicircular rostellum. A key to the species of Aphyllorchis in Thailand is updated

Taxonomic Studies on Thai Anthocerotophyta I. The Genera Dendroceros and Megaceros (Dendrocerotaceae)

A taxonomic review of the hornwort genera Dendroceros Nees and Megaceros Campb. in Thailand is presented, based on herbarium specimens and field surveys. Three species are recognized, namely D. cucullatus Steph., D. suplanus Steph. and M. flagellaris (Mitt.) Steph. A key, descriptions and line drawings and notes on the ecology and geographical distribution of the species are provided

Radula multiflora var. reflexilobula is a synonym of R. decurrens (Radulaceae, Marchantiophyta)

FIGURE 1. Radula decurrens Mitt.: A–B. Portions of sterile plants, ventral views; C. Portion of sterile plants, dorsal view; D. Portion of plant with andoecium; E. Portion of plant with gynoecium; F. Apical cells of leaf lobe; G. Median cells of leaf lobe; H. Basal cells of the leaf lobe. All from B.O. van Zanten 68-2953 (isotype of Radula multiflora Gottsche ex Schiffn. var. reflexilobula Grolle & Yamada, JE).Published as part of Promma, Chatchaba & Chantanaorrapint, Sahut, 2014, Radula multiflora var. reflexilobula is a synonym of R. decurrens (Radulaceae, Marchantiophyta), pp. 174-176 in Phytotaxa 186 (3) on page 175, DOI: 10.11646/phytotaxa.186.3.6, http://zenodo.org/record/514704

Southern Thailand Bryophytes III: A preliminary study on non-epiphyllous taxa in lowland areas

Examination of a collection of non-epiphyllous bryophytes from lowland areas of Phang Nga, Phuket and Surat Thani province yielded 38 liverwort and 29 moss species. Microlejeunea filicuspis (Steph.) Heinrichs. et al., is new to Thailand and additional ten proved to be rarely recorded in this country, being hitherto known only from one other locality. Locality data and habitats are provided for each species and information on oil bodies is given for several species