Molecular phylogenetics and floral evolution of the Cirrhopetalum alliance (Bulbophyllum, Orchidaceae): Evolutionary transitions and phylogenetic signal variation.

The Cirrhopetalum alliance is a loosely circumscribed species-rich group within the mega-diverse genus Bulbophyllum (Orchidaceae). The monophyletic status of the alliance has been challenged by previous studies, although established sectional classifications have yet to be tested in a phylogenetic context. We used maximum likelihood and Bayesian analyses of DNA sequence data (cpDNA: matK and psbA-trnH; nrDNA: ITS and Xdh; 3509 aligned characters; 117 taxa), including all sections putatively associated with the Cirrhopetalum alliance, to reconstruct the phylogeny. We mapped 11 selected categorical floral characters onto the phylogeny to identify synapomorphies and assess potential evolutionary transitions across major clades. Our results unequivocally support the recognition of an amended Cirrhopetalum alliance as a well-supported monophyletic group characterized by clear synapomorphies, following the inclusion of sect. Desmosanthes and the exclusion of five putative Cirrhopetalum-allied sections. Most sections within the Cirrhopetalum alliance are demonstrated to be polyphyletic or paraphyletic, necessitating a new sectional classification. The inclusion of sect. Desmosanthes revolutionizes our understanding of the alliance, with significant evolutionary transitions in floral characters detected. We further investigated six continuously variable characters of the sepals and labellum, and detect phylogenetic conservatism in labellum width and the evolutionary lability of lateral sepal length, which can partly be explained by the different functional roles they play in pollination and pollinator trapping.

Exploring island syndromes: Variable matrix permeability in Phalaenopsis pulcherrima (Orchidaceae), a specialist lithophyte of tropical Asian inselbergs.

Introduction: Plants confined to island-like habitats are hypothesised to possess a suite of functional traits that promote on-spot persistence and recruitment, but this may come at the cost of broad-based colonising potential. Ecological functions that define this island syndrome are expected to generate a characteristic genetic signature. Here we examine genetic structuring in the orchid Phalaenopsis pulcherrima, a specialist lithophyte of tropical Asian inselbergs, both at the scale of individual outcrops and across much of its range in Indochina and on Hainan Island, to infer patterns of gene flow in the context of an exploration of island syndrome traits. Methods: We sampled 323 individuals occurring in 20 populations on 15 widely scattered inselbergs, and quantified genetic diversity, isolation-by-distance and genetic structuring using 14 microsatellite markers. To incorporate a temporal dimension, we inferred historical demography and estimated direction of gene flow using Bayesian approaches. Results: We uncovered high genotypic diversity, high heterozygosity and low rates of inbreeding, as well as strong evidence for the occurrence of two genetic clusters, one comprising the populations of Hainan Island and the other those of mainland Indochina. Connectivity was greater within, rather than between the two clusters, with the former unequivocally supported as ancestral. Discussion: Despite a strong capacity for on-spot persistence conferred by clonality, incomplete self-sterility and an ability to utilize multiple magnet species for pollination, our data reveal that P. pulcherrima also possesses traits that promote landscape-scale gene flow, including deceptive pollination and wind-borne seed dispersal, generating an ecological profile that neither fully conforms to, nor fully contradicts, a putative island syndrome. A terrestrial matrix is shown to be significantly more permeable than open water, with the direction of historic gene flow indicating that island populations can serve as refugia for postglacial colonisation of continental landmasses by effective dispersers.

Corybaspapillatus (Orchidaceae), a new orchid species from peninsular Thailand.

A new species, Corybaspapillatus, is described and illustrated from peninsular Thailand. The new species is easily recognized through a combination of the following characters: the purplish flower, the rounded apex of the dorsal sepal, the outer surface of dorsal sepal covered with irregular papillae in the upper half, the lateral sepals adnate laterally at the base to the connate petals, the V-shaped throat, the labellum bearing short hairs, dentate to erose labellum margins, and well-developed conical spurs. A key to the species of Corybas in Thailand is presented.

Updated description of Diospyrosdussaudii Lecomte (Ebenaceae), with lectotypification and notes on its distribution.

Diospyrosdussaudii is a poorly known species and previous descriptions lacked details about its female flowers and fruits. The species had not been recorded since type collections were made in 1913. As a result of our Diospyros research in Thailand, new specimens and data are now available for this species. In this study, we provide an updated morphological description, illustrations, lectotypification and a distribution map. The species was previously reported to be endemic to Laos; as such, the occurrences in Thailand greatly expand the distribution of the species. In addition, we analysed the phylogenetic relationships between D.dussaudii and other Diospyros species from Southeast Asia and other regions, using DNA sequence data from eight plastid regions. Our phylogenetic analyses indicate that D.dussaudii is closely related to D.castanea, D.dasyphylla and D.insidiosa. Their taxonomic affinities are discussed.

Evaluating the genetic diversity in two tropical leguminous trees, Dalbergia cochinchinensis and D. nigrescens, in lowland forests in Cambodia and Thailand using MIG-seq.

It is vital to measure the levels of genetic diversity and differentiation between populations in a species to understand the current genetic structure and evolution of the species. Here, MIG-seq (multiplexed inter-simple sequence repeat genotyping by sequencing) was employed to assess the genetic variation in two tropical leguminous tree species, Dalbergia cochinchinensis and D. nigrescens, in Cambodia and Thailand. Sequence data for 255-618 loci, each with an approximate length of 100 bp, were obtained, and the nucleotide diversity, Tajima's D and FST were computed. The estimates calculated from the data obtained by MIG-seq were compared to those obtained by Sanger sequencing of nine nuclear coding genes in D. cochinchinensis in our previous study. The nucleotide diversity at the MIG-seq loci was slightly higher than that at silent sites in the coding loci, whereas the FST values at the MIG-seq loci were generally lower than those at the coding loci, although the differences were not significant. Moreover, nucleotide diversities within populations of the two species were similar to each other, at approximately 0.005. Three and four population clusters were genetically recognized in D. cochinchinensis and D. nigrescens, respectively. Although the populations were differentiated from each other, the levels of differentiation among them, as measured by FST, were higher in D. cochinchinensis than in D. nigrescens. This indicates higher levels of gene flow between the populations in the latter species. We recommend using MIG-seq for quick surveys of genetic variation because it is cost-effective and results in smaller variance in the estimates of population genetic parameters.

A new species of Argyreia (Convolvulaceae) from Thailand.

Argyreia pseudosolanum Traiperm & Suddee, sp. nov. from the NE region of Thailand is described and illustrated. The new species is remarkable in having a very distinctive corolla shape similar to Solanum, and staminal filament bases glabrous or nearly glabrous with a few multicellular, uniseriate hairs at the attachment point on the corolla tube. Detailed descriptions, illustrations, a summary of the ecology and an IUCN conservation status are provided.

Cryptocarya kaengkrachanensis, a new species of Lauraceae from Kaeng Krachan National Park, southwest Thailand.

A new species of Lauraceae, Cryptocarya kaengkrachanensis M.Z.Zhang, Yahara & Tagane, from Kaeng Krachan National Park, Phetchaburi Province, southwestern Thailand, is described and illustrated. This species is morphologically most similar to C. amygdalina in that its leaves are pinnately veined, leathery, and apparently glabrous (but microscopically hairy) abaxially, twigs are yellowish brown hairy, and fruits are 1.36 to 1.85 times longer than width. However, C. kaengkrachanensis is distinguished from C. amygdalina in having the leaves of ovate and elliptic (vs. oblong-lanceolate) with leaf aspect ratio (length:width) from 1.38 to 2.28 (vs. 2.46-3.43), and ovoid fruits (vs. ellipsoid) with stalk distinctly swollen (vs. not or only slightly swollen). In addition, phylogenetic trees constructed based on internal transcribed spacer sequences (ITS) and genome-wide SNPs using MIG-seq showed that C. kaengkrachanensis is not sister to C. amygdalina and is distinct from all the other Cryptocarya species hitherto recognized in Thailand. Analysis including other species demonstrates that C. floribunda should be a synonym of C. amygdalina, but we recognize C. scortechinii as a distinct species.

Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): a tale of more than two genera.

A synopsis of the genera Coleus Lour, Equilabium A.J.Paton, Mwany. & Culham and Plectranthus L'Hér. (Lamiaceae, Tribe Ocimeae, Subtribe Plecranthinae) is presented. Generic delimitation follows a recently published molecular phylogeny which identified Coleus as the sister of the remaining genera of Subtribe Plectranthinae; Plectranthus as sister to Tetradenia Benth. and Thorncroftia N.E.Br., and a separate phylogenetically distinct genus Equilabium comprising species previously placed in Plectranthus. In this treatment, 294 species of Coleus, 42 of Equilabium, and 72 of Plectranthus are recognized. All but one of the combinations in Equilabium are new as only the genus and type species have been previously published. Two-hundred and twelve names are changed to combinations in Coleus from Plectranthus, Pycnostachys Hook. and Anisochilus Benth.

Records of Wenchengia (Lamiaceae) from Vietnam.

BACKGROUND: The monotypic genus Wenchengia (Lamiaceae) has been thought to be endemic to Hainan, China. This paper reports on historic records of Wenchengia alternifolia collected from Vietnam. The recent recuration and modernisation of the Paris herbarium greatly facilitated this discovery. NEW INFORMATION: During preparatory work supporting the account for the Lamiaceae of the Flora of Thailand, three specimens of Wenchengia from central Vietnam were found in the Herbarium of the Musuem National d'Histoire Naturelle in Paris (P), and subsequently two duplicates were found in the Herbarium at Kew (K, abbreviations following Thiers 2016). The specimens were collected in and before 1927 and it is not known if the species is still extant in Vietnam. Searches for extant populations should focus in the Ba Na Hills or Bach Ma National Park, central Vietnam.

Phylogeny and evolution of basils and allies (Ocimeae, Labiatae) based on three plastid DNA regions.

A phylogeny of basils and allies (Lamiaceae, tribe Ocimeae) based on sequences of the trnL intron, trnL-trnF intergene spacer and rps 16 intron of the plastid genome is presented. Several methods were used to reconstruct phylogenies and to assess statistical support for clades: maximum parsimony with equally and successively weighted characters, bootstrap resampling, and Bayesian inference. The phylogeny is used to investigate the distribution of morphological, pericarp anatomy, chemical, and pollen characters as well as the geographical distribution of the clades. Tribe Ocimeae is monophyletic and easily diagnosable with morphological synapomorphies. There are monophyletic clades within Ocimeae that broadly correspond to currently recognised subtribes: Lavandulinae, Hyptidinae, Ociminae, and Plectranthinae. Only Lavandulinae has clear non-molecular synapomorphies. Several currently recognised genera are not monophyletic. Floral morphology consistent with sternotribic pollination is most common in Ocimeae, but there are independent departures from this model. Buzz pollination is likely in some species, the only postulated occurrence of this within Lamiaceae. Quinone diterpenoids and flavones in the leaf exudates differ in their distributions across the phylogeny and this could contribute to differences in the recorded medicinal as well as pesticidal uses of the species in the different clades. Mapping geographic distribution on to an ultrametric phylogenetic tree produced using non-parametric rate smoothing supports an Asiatic origin for Ocimeae. There are several secondary occurrences in Asia arising from the African Ociminae and Plectranthinae clades. Colonisation of Madagascar occurred at least five times, and New World colonisation occurred at least three times.