Additions to the orchid flora of Laos and taxonomic notes on orchids of the Indo-Burma region

The following nine new additions to the orchid flora of Laos PDR are reported based on surveys in the country conducted during the period 2012–2017: Bulbophyllum alcicorne, B. meson, Coelogyne suaveolens, Cyrtosia nana, Dendrobium phuketense, Oberonia rhizoides, Phaius columnaris, Thelasis khasiana and Zeuxine longilabris. The taxonomy of a further 15 orchid taxa (Bulbophyllum guttulatum, B. moniliforme, B. sarcophyllum, B. scabratum, B. seidenfadenii, B. tipula, Cleisostoma lecongkietii, Coelogyne ovalis, Dendrobium chapaense, D. crepidatum, D. wattii, Habenaria gibsonii var. foetida, H. malintana, Luisia zeylanica and Phalaenopsis pulcherrima) native to Laos or adjacent countries is reviewed, resulting in the synonymisation of 20 names. In addition, new combinations are made for Grosourdya vietnamica, Luisia sonii and Holcoglossum gaoligongense to bring them in line with recent changes in the classification of the orchid family

Range-wide differential adaptation and genomic vulnerability in critically endangered Asian rosewoods

In the billion-dollar global illegal wildlife trade, rosewoods have been the world’s most trafficked wild product since 2005. Dalbergia cochinchinensis and D. oliveri are the most sought-after rosewoods in the Greater Mekong Subregion. They are exposed to significant genetic risks and the lack of knowledge on their adaptability limits the effectiveness of conservation efforts. Here we present genome assemblies and range-wide genomic scans of adaptive variation, together with predictions of genomic vulnerability to climate change. Adaptive genomic variation was differentially associated with temperature and precipitation-related variables between the species, although their natural ranges overlap. The findings are consistent with differences in pioneering ability and in drought tolerance. We predict their genomic offsets will increase over time and with increasing carbon emission pathway but at a faster pace in D. cochinchinensis than in D. oliveri. These results and the distinct gene-environment association in the eastern coastal edge suggest species-specific conservation actions: germplasm representation across the range in D. cochinchinensis and focused on vulnerability hotspots in D. oliveri. We translated our genomic models into a seed source matching application, seedeR, to rapidly inform restoration efforts. Our ecological genomic research uncovering contrasting selection forces acting in sympatric rosewoods is of relevance to conserving tropical trees globally and combating risks from climate change

Studies on the genus Capparis L. (Capparaceae) in Lao PDR. II: A new species from the Khammouan karst

A new species of Capparis, Capparis lanceolatifolia, is described and illustrated from central Lao PDR, where it is known from a single limestone doline in the Hinboun District, Khammouan Province. The new species is characterized by narrowly lanceolate leaves, racemose inflorescence bearing trifid bracts and small size of flower. Its affinities with related taxa and conservation status are discussed

A new species and two new records of Goniothalamus (Annonaceae) from Lao PDR

Volume: 138Start Page: 17-2

A new species and two new records of Goniothalamus (Annonaceae) from Lao PDR

Goniothalamus saccopetaloides Y.H. Tan & Bin Yang, a new species is described and illustrated from Laos. This species shows morphological similarities to G. yunnanensis W.T. Wang, but it differs from the latter by having almost fleshy, involute and saccate outer petals, subglobose monocarps, and single seeded monocarps. Goniothalamus cheliensis, and G. calvicarpus are new records for the Flora of Lao PDR. A key to Goniothalamus species indigenous to Laos is provided here

An updated checklist of Begonia (Begoniaceae) in Laos, with two new species and five new records

Two new species of Begonia L. (Begoniaceae), B. laotica (sect. Parvibegonia) and B. hypoleuca (sect. Reichenheimia), from north Laos are described and illustrated. Begonia augustinei, B. dryadis, B. lancangensis, B. sizemoreae and B. sillentensis subsp. mengyangensis were newly recorded taxa in Laos. Furthermore, an updated checklist of Begonia of Laos is also compiled

Identifying orchid hotspots for biodiversity conservation in Laos: the limestone karst vegetation of Vang Vieng District, Vientiane Province

A project to study the phytodiversity of the Indo-Burma Biodiversity Hotspot (IBBH) was initiated by Kadoorie Farm and Botanic Garden, Hong Kong, in 2011, with the aim of surveying primary forest fragments and identifying conservation priorities within this expansive but highly threatened ecoregion. Vang Vieng District of Vientiane Province, northern Laos, was chosen as a focus for a pilot expedition, since it features an extensive karst landscape that has barely been explored. Together with officials from the Ministry of Science and Technology, Government of Lao PDR, surveys of three sites were conducted in April 2012, at the end of the dry northeast monsoon season. Emphasis was placed on Orchidaceae because it is among the most species-rich and commercially exploited flowering plant families in the region. A total of 179 specimens were collected, of which approximately 135 were unique taxa accounting for 29.6% of the orchids found in Laos and 5.8% of those found in IBBH as a whole, and equivalent to 0.27 species/hectare within the area surveyed, substantially higher than published figures for other limestone areas in the region, such as Cuc Phuong National Park in Vietnam (0.0055 species/hectare) and Perlis State in Peninsular Malaysia (0.0036 species/hectare).  At least one is a species new to science, nine represent new distributional records for Laos and a further nine are new records for Vientiane Province. A list of the species encountered during the study is presented and the significance of the findings is discussed. Major threats to the natural environment in northern Laos are highlighted.</p

An updated checklist of Begonia (Begoniaceae) in Laos, with two new species and five new records

Volume: 138Start Page: 187-20

Data from: Population genetic structure of the endemic rosewoods Dalbergia cochinchinensis and D. oliveri at a regional scale reflects the Indochinese landscape and life-history traits

Indochina is a biodiversity hot spot and harbors a high number of endemic species, most of which are poorly studied. This study explores the genetic structure and reproductive system of the threatened endemic timber species Dalbergia cochinchinensis and Dalbergia oliveri using microsatellite data from populations across Indochina and relates it to landscape characteristics and life-history traits. We found that the major water bodies in the region, Mekong and Tonle Sap, represented barriers to gene flow and that higher levels of genetic diversity were found in populations in the center of the distribution area, particularly in Cambodia. We suggest that this pattern is ancient, reflecting the demographic history of the species and possible location of refugia during earlier time periods with limited forest cover, which was supported by signs of old genetic bottlenecks. The D. oliveri populations had generally high levels of genetic diversity (mean He = 0.73), but also strong genetic differentiation among populations (global GST = 0.13), while D. cochinchinensis had a moderate level of genetic diversity (mean He = 0.55), and an even stronger level of differentiation (global GST = 0.25). These differences in genetic structure can be accounted for by a higher level of gene flow in D. oliveri due to a higher dispersal capacity, but also by the broader distribution area for D. oliveri, and the pioneer characteristics of D. cochinchinensis. This study represents the first detailed analysis of landscape genetics for tree species in Indochina, and the found patterns might be common for other species with similar ecology