Ba Vuong Truong

Peliosanthes rigidifolia, a new species discovered in central Vietnam, is described and illustrated. It is readily distinguished from all its congeners by its stamens that are entirely free from each other, non-epitepalous, and possess small anthers scarcely exceeding the filaments. A detailed morphological description of the new species is presented along with information on its ecology, phenology, conservation status, and distribution, as well as relevant taxonomic notes and analytical photographic illustrations.

The paper presents a description of Aspidistra pachyloba (Asparagaceae, Convallarioideae), the new species for science, discovered in southern Vietnam. Besides the standard morphological description of the species, data on its ecology, phenology, conservation status, and distribution, as well as relevant taxonomic notes and analytical photographic illustrations, are presented. Discovered plant has unusually long leaves to 1.6 m long and nutant flowers, rare features observed among its congeners. In floral characters the new species is most close to A. truongii from which differs in campanulate flowers 1.9–2.6 cm wide, sepals distinctly larger than petals, anthers 2.5–3.1 mm long, and 6-lobed, gearwheel-shaped stigma, with thick lobes truncate from side-view.

The paper continues a series of contributions on the taxonomic diversity of Psychotria in Vietnam. Three species are revised here for the country. Of them, P. hainanensis represents a new national record, and the presence of P. tutcheri in Vietnam is confirmed for the first time by specimen investigation. For P. prainii, two new synonyms, P. rhodotricha and P. thorelii, are proposed. For each species, a morphological description is compiled and taxonomic and nomenclatural notes are given, along with geographical distribution, notes on their ecology and phenology and analytical illustrations. Lectotypes for three names in Psychotria are designated.

Chiloschista acuticallosa (Orchidaceae, Vandeae, Aeridinae) is described here as a new species to science from Cao Bang Province, Northern Vietnam. The floral shape and color pattern of the new species may lead to misidentification as C. eckhardii, C. glabrisepala, or C. quangdangii. Among these species, our plant morphologically is closest to C. eckhardii but differs in having ovate-oblong lateral lip lobes, a conoid, pointed callus on the lip disc, a trapezoid backwall callus with four irregular teeth, an oblong column foot, and semi-elliptic stelidia. Data on the ecology, phenology, distribution, and relevant taxonomic notes for the new species are presented. The conservation status of the new species is preliminarily assessed as Data Deficient (DD) following the categories and criteria proposed by the IUCN Red List.

A new species of Camellia (section Piquetia) from south-central of Vietnam is described. Within section Piquetia, the new species is most similar to C. honbaensis, but differs in several morphological traits (smaller leaves, longer reddish pedicels, glabrous stamens, and styles completely free from the base). This study provides a standard taxonomic description, together with morphological comparisons between the new species, Camellia honbaensis, with other similar species and additional information on the species habitat, estimated conservation status, and the anatomy of its leaves and branches.

Begonia hanhhoae, a new species from Khanh Hoa Province, Ninh Hoa District, South Central Coast region, Vietnam, is described and illustrated. It resembles B. aspersa from northern Vietnam but differs in having broadly ovate to suborbicular leaves (vs. reniform) with a slightly waxy adaxial surface (vs. velvety), inflorescence with up to 13 flowers (vs. up to 5), actinomorphic androecium (vs. zygomorphic), and pistillate flowers that are subsessile or borne on very short pedicels up to 1.5 mm long (vs. 4–12 mm). According to the IUCN criteria, it has been tentatively assessed as Endangered (EN).

A new species, Hoya thuhae (Apocynaceae, Asclepiadoideae), from lowland areas of central Vietnam, is described. It resembles H. kerrii but may be distinguished by its finely pubescent petioles, puberulous leaf blade, longer peduncle, longer pilose to strigose pedicels, different shape of the calyx lobes, and elliptic corolla segments with apices raised above the central portion. Additionally, H. lobbii, known earlier in NE India, Thailand, and Cambodia, is recorded for Vietnam at first. Data on the ecology, phenology, distribution, and conservation status for both species are provided, together with plates compiled from original color analytical photos.

The paper provides a taxonomic assessment of Bulbophyllum section Racemosae in Vietnam, accompanied by an identification key for all species currently recognized in the country. Information on type specimens, distribution, habitat and phenology (when available), as well as relevant taxonomic notes are presented for each accepted species, accompanied by plates with analytical photos. Bulbophyllum minhquanii is described as new to science, and B. albidostylidium (identified earlier as B. putii) is reported as a new national record. In total, 14 species of B. sect. Racemosae, of which five are endemic, are documented for Vietnam based on previous and current studies. The occurrences of B. macrocoleum and B. morphologorum in Vietnam remain uncertain and require verification by additional collections.

Here we describe a new leafless vine orchid, Vanilla flava Aver., Vuong et V. C. Nguyen (Orchidaceae, Vanilloideae), that we discovered in southern Vietnam (Dak Lak and Gia Lai provinces). It differs from the morphologically closest V. aphylla Blume and V. wightiana Lindl. ex Hook. f. in having large inflorescence up to 4.5 cm long, commonly with 4–9 flowers, a stout peduncle 3–5 mm diam., with 3–6 distant bracts, a pedicel with ovary 2.8–6.4 cm long, 2.2–4 mm diam., and a lip disc with a prominent pack of densely placed, imbricate, backwards-pointing bristles. Data on ecology, phenology, and distribution, as well as relevant taxonomical notes for the new species, are provided. The conservation status of the new species is tentatively assessed as endangered following terms and criteria proposed by the IUCN Red List. The nomenclature of V. wightiana is ­adjusted, its lectotype is designated.

Vanilla baosangii discovered in the Central Highlands of southern Vietnam (Don Duong District, Lam Dong Province), is described and illustrated. In floral morphology the new species is similar to Vanilla siamensis and V. tiendatii in having hairs on the apex of the epichile and hairy column. However, it differs from V. siamensis in fewer, but densely arranged, flattened, often forked hairs on median lip lobe, a verruculose surface between the hairy epichle and bunch of scales, two warty keels forming a groove inside the claw, lip side-lobes surface with four to five distinct verruculose lines, lateral wings of clinandrium prominent, semi-circular, and anther cap ca. 4 mm long, with 2 forward curved horns. From V. tiendatii the new species differs in having larger elliptic leaves 18–26 cm long, an inflorescence bearing up to 25 flowers, lip apex with a group of fat branched hairs 4–7 mm long, and column with dense long hairs at apex, much longer than those in the basal half. According to IUCN Red List Categories and Criteria V. baosangii is assessed as a Critically Endangered. An identification key to all species to Vanilla known in Vietnam is provided, based on recent taxonomic treatments.