Dr Geoffrey Davison Dr Cai Yixong
(Supplement Editor) (Supplement Editor)

Dr David J. Middleton            Dr Jana Leong-Škorničková
(Editor-in-Chief)                   (Managing Editor)

Felicia Tay               Dr Daniel C.Thomas        Christina Soh 
(Graphics Editor)     (Copy Editor)               (Business Manager)

Abstract:
The current paper acts as an introduction to nine following papers concerning the hydrology and biodiversity of Nee Soon freshwater swamp forest. Freshwater swamp forest is a threatened and overlooked ecosystem in the Southeast Asian region and in Singapore. Characterised by predominantly mineral soils supporting forest that contains a subset of flora  and fauna of lowland forest, but with the addition of important habitat specialists, freshwater swamp forest is fed by an array of hydrological processes. As conservation management depends on good hydrological and biological understanding, a research programme was designed to tease out the roles of the various hydrological components. The background, management concerns, and aims of the project are detailed.

Abstract:
The Nee Soon stream drainage in the Central Catchment Nature Reserve is virtually the last remaining fragment of primary freshwater swamp forest in Singapore. The forest type has been poorly studied in the Southeast Asia. The hydrology, water quality, as well as aquatic flora and fauna all have great theoretical and practical significance. The ecology and management of the Nee Soon freshwater swamp forest are reviewed, with remarks on their national, regional and global contexts. This review sets the scene for a three-year integrated conservation and management study completed in 2016.

Abstract:
This paper presents initial findings from research on the hydro-geomorphic status of Nee Soon freshwater swamp forest catchment in Singapore. The hydrological system of Nee Soon contains a swamp that is best described as an organic-rich wetland, with organic matter content as high as 40% near the surface (too low to be classified as peat). Total longterm denudation rate in the catchment is an estimated 23.4 ± 2.08 Mg km-2 yr-1, with physical erosion (5.6 ± 0.5 Mg km-2 yr-1) and chemical weathering (17.8 ± 1.58 Mg km-2 yr-1) accounting for 24% and 76% of the totals, respectively. Age dating of a 1.95-m sediment core from the lower swamp indicates several distinct periods of variable sediment deposition (0.04 to 0.009 cm y-1) since 15,000 BCE, across a variety of climate regimes. A missing layer, representing more than a 7000 year period, verifies substantial channel erosion in the swamp occurring since 1950. Accelerated erosion associated with forest conversion to agriculture in the upper catchment could not be verified through examination of sediment cores. High concentrations of several heavy metals (e.g. As, Cr, Mn, Ni, Sr, V) in the lower catchment, compared with the upper catchment, appear to be natural (e.g. related to differences in the underlying bedrock), rather than contamination. The very high concentrations of lead, copper, and zinc associated with firing activities in the military range in the lower catchment are spatially isolated (e.g. shooting berms), and currently not posing a threat to the swamp environment. Other hydrogeomorphic degradation processes/activities now include disruption to hillslope soils and streams by trampling and mountain biking, back-flow of reservoir release water into the lower swamp area, and atmospheric deposition of contaminants.

Abstract:
The unique plant communities of the freshwater swamp forests of southern Johor (Malaysia) and Singapore attracted the attention of E.J.H. Corner, but there have been no comprehensive follow-up studies to his seminal work. Meanwhile, freshwater swamp forests in the region have been mostly lost to logging and in-filling for plantations or urban development. The Nee Soon catchment contains the last substantial tract of this forest type in Singapore. We collated the rediscoveries of vascular plant species presumed Nationally Extinct in the 2nd and latest edition of the Singapore Red Data Book, and new records for the Singapore vascular plant flora from the Nee Soon catchment, including those that we found and collected through the establishment and survey of 40 vegetation plots, each 20 × 20 m. We have identified 672 species from 117 families, of which 288 are trees from 60 families represented by at least one stem ≥ 5 cm DBH. The catchment is especially species rich and abundant in the Myristicaceae. In the last ten years, 53 rediscoveries, 11 new species records, and two new varietal records have been uncovered from (or can be found in) the Nee Soon catchment. The Nee Soon freshwater swamp forest is one of Singapore’s most valuable botanical areas, and warrants sustained conservation effort and study.

Abstract:
The Nee Soon freshwater swamp forest is a vital area for biodiversity conservation in Singapore. A survey of the aquatic macroinvertebrates in the streams of the Nee Soon drainage was carried out to capture a representative sample of the communities present. Here, we present the different groups of macroinvertebrates sampled as well as their abundance and distribution within the freshwater swamp forest. An annotated checklist of the orders of the macroinvertebrates found in the freshwater swamp forest follows, together with information on their distribution and abundance within the Nee Soon catchment.

Abstract:
Nee Soon freshwater swamp forest is the last remaining primary freshwater swamp forest left in Singapore and it contains a rich diversity of native and locally threatened fauna. As native terrestrial snails and slugs are poorly studied and understood in Nee Soon freshwater swamp forest, an extensive survey was conducted to establish their current status. A total of 19 species was recorded, of which one was recorded for Singapore for the first time. Amphidromus atricallosus temasek, a recently described subspecies endemic to Singapore, was found to be more commonly distributed than previously known from the swamp forest. Results also indicate that despite low overall abundance, Nee Soon freshwater swamp forest harbours a rich diversity of land snails and slugs. Any future long term changes in climate or topography, or short term changes in hydrology, might affect their distribution and diversity.

Abstract:
Biodiversity baselines were established for dragonflies of Nee Soon freshwater swamp forest based on quantitative sampling across the eight sub-catchments. Surveys were conducted from December 2014 to April 2016. Hydrological, physiochemical parameters and habitats were analysed to identify the main drivers structuring the dragonfly community. A total of 1706 odonate specimens were recorded, comprising 49 species of 34 genera in 11 families. The species diversity in each sub-catchment was compared using the Shannon-Wiener Index (H’). Hierarchical clustering and Detrended Correspondence Analysis (DCA) indicated that three main groupings of sites existed, each with a distinct community of associated species. Further analysis by Canonical Correspondence Analysis (CCA) with 12 significant environmental variables showed that these groups were significantly associated with respective environmental variables. Principal Components Analysis (PCA) was performed to analyse the full 23 environmental variables. The first four principal components of the PCA explained 63% of the variation in all the environmental variables. These four axes were input as independent variables into an Ordinary Least Square (OLS) model to test the significance of the link between habitat characteristics and diversity of the dragonfly community. Threats to the odonate fauna of the freshwater swamp forest are identified and conservation management measures are discussed.

Abstract:
Many invertebrate and plant species are difficult to identify even by taxonomic experts. This has created a major obstacle for understanding the ecology of tropical environments. Here we explore the use of new large-scale, cost-effective approaches to species identification using Next-Generation Sequencing (“DNA barcodes”). Due to the rapid drop in sequencing cost, such barcodes have the potential to help with many identification tasks and they will facilitate regular monitoring of habitats. We use this approach to explore the species diversity of Nee Soon freshwater swamp forest and provide taxonomic identification tools for the fauna and flora of the forest. DNA-barcode libraries were generated for the flora (>1000 barcodes; 170 chloroplast genomes) and fauna (ca. 3000 barcodes). In addition, highresolution images of 502 animal and 200 plant species were placed on an online image database (“Biodiversity of Singapore”). These images are available to help experts and non-experts alike to identify and appreciate these species. The new databases document Nee Soon’s impressive diversity, but they are also important for in-depth studies of fauna-floral species interactions. For example, the plant barcodes were used to reconstruct the diet of Raffles’ banded langur based on faecal samples. Overall, we find that the fauna in Nee Soon freshwater swamp forest is very diverse and includes many rare species, and that the species composition is very distinct from those living in surrounding habitats. Animal specimens are readily sequenced, while plant specimens (especially those represented by sapwood samples) remain a challenge. However, newer techniques (e.g. based on genome skimming) are starting to help with obtaining plant DNA-barcodes.

Abstract:
As Singapore’s only remaining patch of primary freshwater swamp forest, the good management of the Nee Soon catchment is of utmost importance if a large proportion of the flora and fauna in Singapore is to be conserved. An integrated eco-hydrological model is developed for the area, with the objectives to numerically model the hydrological variations, to assess the possible impacts of future climate change, and to facilitate future ecohydrological management. The numerical model considers the hydrological processes in a holistic manner, including rainfall-runoff, evapotranspiration, the interaction between surface water and groundwater, etc. The numerical model makes use of a combination of field survey data and alternative remote sensing data. With climate projection inputs from the Regional Climate Model (RCM), the numerical model is applied to run future scenarios to assess the climate change impact. A few management strategies are considered if favourable hydrological conditions are to be maintained for conserving the local ecosystem.

Abstract:
The current paper acts as a summary to the “Nee Soon Swamp Forest biodiversity and hydrology baseline studies project”, including results published previously and the results from papers of the current volume. Overall, flora and fauna surveys indicate healthy and diverse plant, fish and aquatic macroinvertebrate communities in Nee Soon freshwater swamp forest. There are some concerns over terrestrial and aquatic alien invasive species, loss of big emergent trees, small population sizes and viability of various native species, and the uncertain outcomes of changes in water quality and quantity. The findings inform management that Nee Soon freshwater swamp forest is especially vulnerable to changes in hydrology and there is much dependency on precipitation for its water budget. Projected climate change effects on precipitation and statistical analyses of biotic responses to hydrology clearly define drought as a major, perhaps the foremost, source of vulnerability to the ecosystem functioning of Nee Soon freshwater swamp forest. Potential management solutions are suggested to address five issues of concern for the forest: hydrological integrity, erosion and sedimentation, ecological integrity, the impact of the spillway, and impacts of construction and development.

Content Page

Abstract: 
Hanguana podzolicola (Hanguanaceae) is newly recorded for Singapore. Detailed colour plates are given alongside the main characters for distinguishing this species from the two most similar species in Singapore, Hanguana rubinea and H. triangulata. The seeds of Hanguana podzolicola are described for the first time. A local conservation assessment is given. As no original material of Hanguana podzolicola could be traced, a neotype is designated here. Following a recent clarification of several historical Hanguana names it is noted here that the correct name for the large helophytic stoloniferous species often cultivated in Singapore under the name Hanguana malayana is Hanguana anthelminthica. An updated key to Hanguana species in Singapore is provided.

Abstract:
Two species of Litsea (Lauraceae) are recorded for Singapore for the first time (Litsea spathacea Gamble and L. tomentosa Blume). Both species are known only from 19th century specimens and must be considered nationally extinct in Singapore. Descriptions and notes on distribution, conservation status and ecology are given. In addition, twenty-two Lauraceae names are lectotypified: Beilschmiedia curtisii Gamble, B. perakensis Gamble; Cinnamomum subavenium Miq.; Cryptocarya argentea Gamble, C. infectoria (Blume) Miq., C. tomentosa Blume; Lindera lucida (Blume) Boerl., L. malaccensis Hook.f.; Litsea accedens (Blume) Boerl., L. amara Blume var. attenuata Gamble, L. gracilis Gamble, L. gracilipes Hook.f., L. griffithii Gamble, L. lanceolata (Blume) Kosterm., L. machilifolia Gamble, L. machilifolia Gamble var. angustifolia Gamble, L. megacarpa Gamble, L. pustulata Gamble, L. sarawacensis Gamble, L.singaporensis Gamble, L. spathacea Gamble, L. umbellata (Lour.) Merr.

Abstract:
The genus Epirixanthes Blume is revised for Brunei Darussalam. Four species are recognised for the country: Epirixanthes cylindrica Blume, E. elongata Blume, E. kinabaluensis T.Wendt and E. papuana J.J.Sm., with the two latter species being newly recorded for the Brunei flora. A single collection from Brunei that was formerly identified as Epirixanthes pallida T.Wendt is now confirmed as E. papuana. A revised key for the genus is included.

Abstract:
Zingiber Mill. is distributed from India to the Pacific but only a few species are known from east of Wallace’s Line, whereas the area to the west is rich in species. A recent collection from limestone at Bantimurung, South Sulawesi, Indonesia represents a new eastern species, Zingiber ultralimitale Ardiyani & A.D.Poulsen, which is described, illustrated, and barcoded using three of the four barcoding loci (rbcL, trnH-psbA and ITS). Placement of this species using morphological evidence is ambiguous but a combination of evidence from morphology, pollen anatomy and molecular analysis indicates that it belongs to Zingiber sect. Zingiber.

Abstract:
Syzygium jiewhoei Hambali, Sunarti & Y.W.Low, a new species from Western New Guinea, Indonesia, is described and illustrated. It is closely related to Syzygium recurvovenosum (Lauterb.) Diels but differs in a range of vegetative and reproductive morphological characteristics.

Abstract: 
Microchirita (C.B.Clarke) Yin Z.Wang (Gesneriaceae: Didymocarpoideae) in Thailand is revised and 29 species are recognised, two of which have three varieties each. Eight new species are described, Microchirita albocyanea C.Puglisi, Microchirita glandulosa C.Puglisi, Microchirita hypocrateriformis C.Puglisi, Microchirita limbata C.Puglisi, Microchirita luteola C.Puglisi, Microchirita tadphoensis C.Puglisi, Microchirita tetsanae C.Puglisi, Microchirita thailandica C.Puglisi; three new varieties are described, Microchirita involucrata var. gigantiflora C.Puglisi, Microchirita mollissima var. glabra C.Puglisi, Microchirita mollissima var. glandulophylla C.Puglisi; and one name is combined at a new rank, Microchirita involucrata var. capitis (Craib) C.Puglisi. Two lectotypifications are made, one of which is a second step lectotypification. A key to all taxa is given, all taxa are described, and many are illustrated.

Abstract:   

Abstract:
Two new species of Oreocharis (Gesneriaceae), O. argyrophylla W.H.Chen, H.Q.Nguyen & Y.M.Shui and O. blepharophylla W.H.Chen, H.Q.Nguyen & Y.M.Shui, from the Xuan Nha nature reserve, Van Ho district, Son La province, in northwestern Vietnam are described. They are compared to their most similar species and diagnostic characteristics are provided.

Abstract: 
A new species, Primulina wuae F.Wen & L.F.Fu (Gesneriaceae), is described from the southern part of China. This new species is most similar to Primulina pseudoroseoalba Jian Li et al., P. roseoalba (W.T.Wang) Mich.Möller & A.Weber, P. subrhomboidea (W.T.Wang) Yin Z.Wang and P. beiliuensis B.Pan & S.X.Huang var. fimbribracteata F.Wen & B.D.Lai, but differs from these in characters such as the size and indumentum of the bracts, the indumentum of the pedicels and anthers, the length of the pistils etc. A provisional conservation assessment is also provided.

Content Page

Abstract: 
A revision of Microchirita (C.B.Clarke) Yin Z.Wang (Gesneriaceae) in Malaysia is presented as a precursory paper for the Flora of Peninsular Malaysia account. The taxonomic treatment includes a key for identification, detailed descriptions of the species, information on seed morphology (illustrated by Scanning Electron Microscopy micrographs), and a discussion on distributions, including maps, and the conservation status for each species.

Abstract:
Types of all Hoya species occurring in Borneo and their synonyms are indicated and clarified. Forty-six lectotypes, nine neotypes and five epitypes are designated.

Abstract:
Macrosolen brunsing Y.W.Low & Ariffin is described and illustrated here as a new species of aerial hemiparasite based on two collections from the Ladan Hills Forest Reserve, Tutong, Brunei Darussalam. The new species differs from all Macrosolen taxa enumerated in Borneo by its distinct linear leaves ((4–)8–14.5 cm long, 0.1–0.2(–0.25) cm wide).

Abstract:

Abstract:
A total of 72 species of liverworts have been found in Bali. Based on recent collections and former records of the species including 31 genera and 17 families, among them, 43 species are new to Bali.

Abstract:
Begonia ignita C.W.Lin & C.I Peng, a new species of Begonia sect. Petermannia from Sulawesi, Indonesia, is here described and illustrated. It is distinct from other species in Begonia section Petermannia by a character combination including a procumbent stem ascending only at the apex, symmetric or subsymmetric leaves, the presence of a pale band or maculation running parallel to the leaf margin, and orange tepals. A detailed comparison with a morphologically similar species, the Sulawesi endemic Begonia mendumiae M.Hughes, is provided.

Abstract: 
The large majority of Hoya R.Br. species known from Papuasia were described in the first half of the 20th century and most of these are endemic. Along with Borneo and the Philippines the region is a centre of diversity of the genus. Since 2006 herbarium materials have been studied for a revision of Hoya of New Guinea along with field investigations on Papuasian Hoya since 2010. In the present paper we publish ten new species, Hoya brassii P.I.Forst. & Liddle ex Simonsson & Rodda, H. carrii P.I.Forst. & Liddle ex Simonsson & Rodda, H. edholmiana Simonsson & Rodda, H. evelinae Simonsson & Rodda, H. juhoneweana Simonsson & Rodda, H. krusenstierniana Simonsson & Rodda, H. koteka Simonsson & Rodda, H. stenakei Simonsson & Rodda, H. versteegii Simonsson & Rodda and H. yvesrocheri Simonsson & Rodda, one subspecies, H. juhoneweana ssp. lindforsiana Simonsson & Rodda, and make one new combination, H. urniflora (P.I.Forst.) Simonsson & Rodda, which is also lectotypified.

Abstract: 
In preparation for a new checklist of Singaporean plants, the Flora of Singapore project, and the Ferns of Thailand, Laos and Cambodia website, new combinations in Aglaomorpha Schott are made to accommodate species formerly placed in Drynaria (Bory) J.Sm. and Christiopteris Copel. Ten names are lectotypified, seven of which are second step lectotypifications, and one name is neotypified.

Content Page

Abstract: 
After critical study of type material and all available collections, the identity of Hoya wallichii (Wight) C.M.Burton as a species distinct from Hoya campanulata Blume is clarified. Hoya wallichii was previously considered to be endemic to Singapore but had become nationally extinct and consequently globally extinct. This study reveals, however, that it is also found in Peninsular Malaysia and Brunei and, even though it is still nationally extinct in Singapore, it is no longer globally extinct. Hoya campanulata is widespread and locally common in Sundaland but also nationally extinct in Singapore. The two species are fully described and illustrated by line drawings and colour photographs. Two conservation assessments are made, three names are lectotypified, and one name is epitypifed. This paper exemplifies how critical taxonomic understanding is fundamental to meaningful conservation assessments.

Abstract:
The species of Lamiaceae have recently been revised for Singapore. In total 44 species in 21 genera are recorded, of which 23 species are native, an additional five are probably native, and 16 are non-native species which have naturalised in Singapore. One new record for Singapore has been found (Vitex rotundifolia) and one species reinstated (Callicarpa pentandra) after being ignored for over a hundred years.

Abstract:
An account of the genus Hexapora (Lauraceae) is presented. It comprises morphological descriptions of the genus and species, a provisional IUCN conservation assessment, ecological information and taxonomic notes. The morphology of the genus is compared to that of a number of possible close relatives, leading to the conclusion that it most likely belongs within the Beilschmiedia clade, and is likely closely related to Sinopora.

Abstract:
Hanguana fraseriana, a new species from Peninsular Malaysia, is described and illustrated here.

Abstract:
Four nomenclatural updates, viz. Ternstroemia coriacea, T. palembangensis, T. penangiana and T. wallichiana, and two new records T. patens and Eurya glabra in Peninsular Malaysia are presented.

Abstract:
Peninsular Malaysian Impatiens foxworthyi M.R.Hend. is distinct from the Thai I. opinata Craib. Three new Impatiens species are described: I. glaricola Kiew with purple flowers, I. chikuensis Kiew with pale yellow flowers, and I. vinosa Kiew with deep red flowers. While Impatiens foxworthyi is widespread on karst limestone in Kelantan and Pahang, the three new species are narrowly endemic to Kelantan limestone and are critically endangered.

Abstract: 
Four new species, Begonia kanaensis Kiew & C.Y.Ling, Begonia lingiae S.Julia, Begonia rubrotepala S.Julia and Begonia sadirensis Kiew & S.Julia are described from Sarawak, Borneo. Notes on habitat, distribution and additional specimens examined for Begonia calcarea and B. sabahensis are also provided. A key to the species in the ‘calcarea group’ is provided. The status of the ‘calcarea group’ as belonging to Begonia sect. Diploclinium or to a new section is discussed. A provisional conservation status is assigned to each species.

Abstract: 
Eight new Begonia (Begoniaceae) species, Begonia addrinii S.Julia & Kiew, Begonia celata S.Julia & Kiew, Begonia crassa S.Julia & Kiew, Begonia devexa S.Julia & Kiew, Begonia fractiflexa S.Julia & Kiew, Begonia hirtitepala S.Julia & Kiew, Begonia jamilahanuiana S.Julia and Begonia ubahribuensis S.Julia & Kiew, are described from Lanjak Entimau Wildlife Sanctuary and Batang Ai National Park in Sarawak, Malaysia. Two and four species are only known from Batang Ai National Park and Lanjak Entimau Wildlife Sanctuary respectively while two species are found in both sites. Seven species belong to Begonia sect. Petermannia and the placement of one (Begonia fractiflexa) is uncertain.

Abstract:
A new species of Begonia, Begonia nephrophylla Undaharta & Ardi, is described from Manusela National Park, Seram Island, Moluccas, Indonesia. The species is endemic to Seram and belongs to Begonia section Petermannia. An illustration of the new species and a key to the Moluccan species of Begonia is presented.

Abstract:
Two new ginger species from central Vietnam, Etlingera poulsenii Škorničk. and Hornstedtia bella Škorničk., are described and illustrated here.

Abstract: 
The taxonomic history of Boesenbergia Kuntze (Zingiberaceae) in Myanmar is reviewed. Based on specimen records eight species are currently confirmed as occurring in Myanmar. These include two new records, Boesenbergia albomaculata S.Q.Tong and B. kerrii Mood, L.M.Prince & Triboun. Two previously listed species, Boesenbergia plicata (Ridl.) Holttum and B. thorelii (Gagnep.) Loes., are not considered here due to lack of specimens originating in Myanmar. A key to the species is provided with a description of each based on living material.

Abstract:
The species Memecylon cerasiforme Kurz was previously known only from the type which was collected in Chittagong, Bangladesh. A recent collection of the species from the Jaldapara National Park, West Bengal, India is not only the first since the species was described in 1877 but also the first record of its occurrence in India and the first flowering collection. Its flowers can now be described and illustrated for the first time. An emended description, figure, phenological and habitat information, notes on related species, and a conservation assessment are also provided. The only original material available at Kew is designated here as a lectotype.

Abstract:
Flora Malesiana, series I – Seed Plants. Volume 22: Lythraceae. W.J.J.O. de Wilde & B.E.E. Duyfjes. P.C. van Welzen (Ed.) 2016.

Content Page

Abstract: 
The genus Aeschynanthus Jack is revised for Singapore and Peninsular Malaysia. Four species for Singapore and fourteen species for Peninsular Malaysia are recognised, keys to the species are given, all names are typified, and detailed descriptions of all species are provided. Conservation assessments are provided for all species. Eleven names are lectotypified here and one epitype is designated.

Abstract:
Notes concerning the three genera Alphonsea Hook.f. & Thomson, Artabotrys R.Br. ex Kew Gawl. and Stelechocarpus Hook.f. & Thomson (Annonaceae) for the Malay Peninsula are presented. Alphonsea kingii J.Sinclair is accepted as an endemic species and a second-stage lectotypification is presented for Alphonsea cylindrica King. Seven species of Artabotrys are lectotypified. The recently described genus Winitia Chaowasku is reduced to Stelechocarpus and a new combination is made for Winitia expansa Chaowasku.

Abstract:
A new species, Polyalthia watui, is described. It resembles Polyalthia bullata King in having bullate leaves with a cordate base, but is distinguished by its flowers with shorter pedicels, longer sepals and petals, subsessile monocarps with long stiff erect hairs; and broad-obovate leaves with fewer pairs of secondary veins. The new species is only known from Brunei’s Belait and Tutong districts and is very likely endemic to the Belait geosyncline that includes these areas.

Abstract:
Three new species of Begonia L., Begonia sumbawaensis Girm., Begonia brangbosangensis Girm. and Begonia jaranpusangensis Girm., are described from Sumbawa, Indonesia. All species are illustrated and identification keys and distribution maps are provided.

Abstract:
During plant inventory work in the forested areas of Mt Mesehe and Mt Merbuk, Jembrana district, Bali, twenty orchid species were collected. Among the species collected, five were confirmed as new records for Bali. The five newly recorded species are Calanthe zollingeri Rchb.f., Plocoglottis plicata (Roxb.) Ormerod, Podochilus serpyllifolius (Blume) Lindl., Styloglossum speciosum (Blume) T.Yukawa & P.J.Cribb, and Vanilla albida Blume. Descriptions of taxa and images are provided.

Abstract:
A new name, Olea luzonica Kiew, is proposed to replace the later homonym Olea obovata (Merr.) Kiew.

Abstract: 
Begonia khaophanomensis Phutthai & M.Hughes is described from a collection made on granitic rock in Krabi Province in Peninsular Thailand. It is endemic to the typelocality of Khao Phanom Bencha National Park, and is assessed as Least Concern using the IUCN criteria. Begonia macrotoma Irmsch. is noted as a new record for Thailand from collections in Chiangmai, Nakhon Ratchasima and Nakhon Nayok provinces; the species is also found in China, Myanmar, NE India, Nepal and Vietnam. Both species belong to Begonia sect. Platycentrum. A key to the species of Begonia sect. Platycentrum in Thailand is provided.

Abstract: 
Boesenbergia albosanguinea (Ridl.) Loes. (Zingiberaceae) is resurrected from the synonymy of B. prainiana (King ex Baker) Schltr. It is redescribed in detail with comparative tables, figures, and illustrations. This species is a new record for Thailand.

Abstract:
Boesenbergia siphonantha (King ex Baker) M.Sabu, Prasanthk. & Škorničk. (Zingiberaceae) is newly recorded from Thailand and Vietnam. Its nomenclatural history, taxonomy, and molecular phylogeny are discussed. Figures, a comparative table and a watercolour illustration are provided.

Abstract:
A new species, Boeica ornithocephalantha F.Wen, Y.G.Wei & T.V.Do (Gesneriaceae), is described from the northern part of Vietnam. This new species is most similar to Boeica ferruginea Drake, but clearly differs from the latter by the unusual corolla. A provisional IUCN conservation assessment is provided.

Abstract: 
Based on molecular, morphological and cytological studies the previously monotypic genus Deinostigma W.T.Wang & Z.Y.Li has been expanded to include several species previously ascribed to Primulina Hance. Deinostigma now comprises seven species, including one previously placed in synonymy. The new combinations Deinostigma cicatricosa (W.T.Wang) D.J.Middleton & Mich.Möller, Deinostigma cycnostyla (B.L.Burtt) D.J.Middleton & H.J.Atkins, Deinostigma cyrtocarpa (D.Fang & L.Zeng) Mich.Möller & H.J.Atkins, Deinostigma eberhardtii (Pellegr.) D.J.Middleton & H.J.Atkins, Deinostigma minutihamata (D.Wood) D.J.Middleton & H.J.Atkins and Deinostigma tamiana (B.L.Burtt) D.J.Middleton & H.J.Atkins are made. Deinostigma eberhardtii is lectotypified. The genus is defined by a combination of an alternate leaf arrangement, hooked hairs on many plant parts, flowers with the pedicel inserted at an angle and off-centre on the receptacle, and, where known, a somatic chromosome number (2n) of < 36. This new circumscription of the genus expands its distribution from Vietnam into South China.

Abstract:
The nomenclatural history of Monolophus Delafosse, Guill. & J.Kuhn is discussed. The combinations Monolophus picheansoonthonii (Phokham & Prasarn) Veldk. and Monolophus pubescens (Picheans. & Phokham) Veldk. are made.