Sonerila taynguyenensis Dinh, C.H. Nguyen & C.W. Lin (Melastomataceae) is described as a new species from the Central Highlands of Vietnam. It is morphologically similar especially to S. montana in its erect habit, ovate-lanceolate leaves and the presence of gland-tipped trichomes on the pedicels and hypanthium. It can, however, be readily distinguished by having a quadrangular to obtusely quadrangular stem (vs. terete), acrodromous to subacrodromous venation (vs. pinnate), larger petals up to 16 × 7 mm (vs. up to 9.5 × 6 mm) and 7–8 mm long anthers (vs. ca. 6.5 mm). Sonerila taynguyenensis is also compared with S. tenue. Based on the available data and following the IUCN Red List Categories and Criteria, S. taynguyenensis is tentatively assessed as Least Concern (LC).

Perilimnastes dongchauensis (Melastomataceae), apparently endemic to Quang Tri province, Central Vietnam, is described here as a new species. It closely resembles P. suberalata in having elliptic-lanceolate leaf blades, few-flowered inflorescences, 4-merous flowers, and similar anther morphology. However, it differs in several key characteristics, with stems and petioles densely setose (vs. glabrous), leaves equal or subequal in a pair (vs. unequal, rarely subequal) and adaxial surface setose (vs. glabrous), hypanthia setose (vs. glabrous), calyx lobes narrowly triangular (vs. linear), and petals much larger, measuring 17–20 × 13–18 mm (vs. ca. 6 × 3.5 mm).

Begonia thanhquyetii, a new species from central Vietnam, is herein described and illustrated. It is morphologically most similar to B. baik in its creeping habit, rugose ovate leaves, and protogynous inflorescences. However, it differs in several key morphological characters, including stipules hirsute on the abaxial surface (vs. glabrous), bracts lacking glandular hairs along the margins (vs. glandular-ciliate), a pair of bracteoles present near the apex of the pistillate pedicel (vs. bracteoles absent), abaxial tepals of both staminate and pistillate flowers hirsute (vs. glabrous), and densely hirsute ovary (vs. glabrous). Following the IUCN Red List Categories and Criteria (Version 16), B. thanhquyetii is provisionally assessed as Least Concern (LC), pending further field surveys to clarify its distribution and population status.

The plant species Impatiens chamchumroonii of the Balsaminaceae family was recorded for the first time in Vietnam. They are collected from Dak Lak province hill areas in 2023. The voucher specimens of this species are housed in the herbarium of the Vietnam National University of Forestry (VNF). The species is presented with a taxonomic description, ecology, geographical distribution, occurrence in Vietnam, and field photographs of new records.

Impatiens damrongii Shimizu, previously known as a native species of southern China, northern Laos, and northern Thailand, is found first in Vietnam, in the Nam Dong Conservation Area (Thanh Hoa Province). The voucher herbarium specimens of this species collected in Vietnam are housed in the herbarium of the Vietnam National University of Forestry. A morphological description of this species, accompanied by color photographs, data on ecology and phenology in Vietnam are additionally provided.

The paper presents new data on the orchid diversity of Vietnam obtained mainly during the fieldwork of 2023–2024, as well as a result of investigation of the herbarium and garden collections of Russia and Vietnam. It includes five species new to science, namely Cleisostoma truongquanii, Cymbidium bavuongii, Hemipilia uniflora, Micropera vietnamensis, Robiquetia binhii, and one variety, Biermannia averyanovii var. micrantha. Six species, Biermannia brachystachys, Cleisostoma nangongense, Coelogyne cumingii, Eulophia bicallosa, Gastrodia fontinalis, and Schoenorchis seidenfadenii are reported for Vietnam at first. For each of the studied taxa, their types, relevant synonyms, studied specimens, ecology and phenology (within Vietnam), distribution, preliminarily assessed conservation status, brief taxonomic notes and illustrations are provided. For the newly described taxa, morphological descriptions and notes on etymology are included. In addition, new nomenclature combinations, Panisea lecongkietii (Vuong, Aver. & Q.T.Truong) Aver., Biermannia brachystachys (Schltr.) Aver., Thrixspermum arunachalensis (A.N.Rao) Aver., and Thrixspermum jainiana (S.N.Hegde & A.N.Rao) Aver. are proposed. Based on available literature data and currently presented data the orchid flora of Vietnam includes 1382 species belonging to 184 genera.

A new species of Spatholirion (Commelinaceae), S. wuorum, from North Vietnam is here described and illustrated. Spatholirion wuorum resembles S. cucphuongense in its dwarf habit and variegated leaves, but differs in having (sub)appressed sericeous or tomentose petioles (vs. retrorse velutinous), lamina sparsely pilose on the adaxial surface (vs. minutely appressed puberulous), the staminate part of the inflorescence a panicle (vs. raceme), and the sepals and petals whitish green or very pale creamy white tinged grayish mauve towards the apex (vs. uniformly dark indigo).

Over the past decade, our understanding of Begonia diversity in Vietnam has steadily grown, with numerous new taxa described. Most Begonia species in Vietnam exhibit highly restricted to moderately limited distributions, and many others have yet to be formally described and named. As part of our ongoing research on Vietnamese Begonia, we identified several previously unknown species within the country. After thorough morphological examination and a comprehensive review of the literature, we found that the characteristics of these specimens did not match any currently described Begonia species from Indochina, leading us to conclude that they are new to science. Here, we describe five new species: Begonia quangnamensis, B. zonata, B. thuanchauensis, B. lii and B. ducii.

Ophiopogon rugosus, a new species from Thai Nguyen Province (formerly Bac Kan Province), NE Vietnam, is described and illustrated. It is distinguishable from all other members of the genus by its elliptic leaf blades with many small wrinckles arrayed in a checkered pattern on the adaxial surface. Somewhat resembling O. xylorrhizus in its habit and rigid roots, the new species clearly differs mainly by the smaller, adaxially wrinkled, abaxially white-glaucous (vs. pale green) leaf blades with fewer longitudinal parallel veins. Besides morphological and ecological data, we provide notes on its relationships to several similar species.

The paper reports Aspidistra nigrescens, as a new species to science discovered in central Vietnam (Quang Binh Province). It provides species diagnosis, standard description, color illustrations, data about type specimens, ecology, phenology, distribution, preliminarily estimated conservation status, and notes about closely allied related species. Discovered species belongs to “A. zinaidae group”, species of which (A. erosa, A. heterocarpa, A. multiflora, and A. zinaidae) shares such characters as small, 6-morous, campanulate or urceolate flowers with dark purple to black lobes of perigone, and stamens inserted near middle of perigone tube. The group is morphologically well segregated and forms rather isolated, monophyletic, highly supported clade in molecular cladistics. An identification key of species belonging to “A. zinaidae group” is provided. Among members of this group newly discovered species morphologically is most close to A. heterocarpa sharing such particular character as cylindric, drumstick-shaped pistil hardly broadening at the base and apex.

The paper presents new data on the orchid diversity of Vietnam obtained mainly in the course of the fieldwork in 2020–2023, as well as from the investigation of the collections stored at the Herbaria of Russia and Vietnam. It includes descriptions of four species (Appendicula spicata, Dendrobium khanhii, D. vietii, Listera anthropophora) and one variety (Eria dacrydium var. cornuta) new to science, as well as reports of 18 species new to the flora of Vietnam (Bulbophyllum conchiferum, B. gibbosum, B. lasiochilum, B. malleolabrum, B. medusae, B. mucronatum, B. reclusum, B. siamense, B. sutepense, Dendrobium deltatum, D. densiflorum, D. lampongense, D. polyanthum, Oberonia maxima, Phreatia sulcata, Podochilus lucescens, Sunipia grandiflora and S. rimannii). In addition, a new name, Dendrobium nobile var. luteoalbum, and a new nomenclatural combination, Eria chienii, are proposed, and lectotypes for the names Bulbophyllum mucronatum, B. sutepense, Dendrobium deltatum and D. nobile var. luteoalbum are designated. For each of the studied species, relevant synonyms, studied specimens, ecology, phenology, distribution, conservation status assessment according to the IUCN Red List Categories and Criteria, brief taxonomic notes, and illustrations are provided. For the newly described taxa, morphological descriptions and notes on etymology are included.

A new species of Begonia sect. Platycentrum, Begonia nahauensis, is described based on morphological characters. The new species is morphologically similar to B. auritalata, however, it is clearly distinct from the latter due to its petioles and ovary, which are densely covered with gland-tipped hairs (vs. non-glandular hairs), capsule with three complete locules (vs. three locules, but one of them is either underdeveloped or degenerated) and three straight wings (vs. adaxial wing being concave). A morphological description and diagnosis, information on distribution and ecology, and a preliminary conservation assessment are provided.

The paper presents new data on the orchid diversity of Vietnam obtained mainly during the fieldwork of 2020–2023, as well as a result of investigation of the herbarium collections of Russia and Vietnam. It includes two species new to science, Bidoupia micrantha and Hylophila vietnamensis, and three species new to the native flora of Vietnam, i.e. Diphylax urceolata, Disperis neilgherrensis, and Habenaria siamensis. Three genera, Diphylax, Disperis and Hylophila, are reported here for the flora of Vietnam for the first time. In addition, a newly naturalized species Cynorkis fastigiata is documented, which originates from the Comoros, Madagascar, the Seychelles, and the Mascarenes. For each of the studied species, its type, relevant synonyms, studied specimens, ecology and phenology (within Vietnam), distribution, preliminarily assessed conservation status, brief taxonomic notes and illustrations are provided. For the newly described taxa, morphological descriptions and notes on etymology are additionally included.

Species of Impatiens hirsutisepala new distribution central Vietnam, the new record species shows similarities with I. hirsutisepala shows similarities with Impatiens marianae in its creeping densely pilose stem, petiole, lamina, densely pubescent inflorescence axis, lateral sepals, lower sepal, curved spur, dorsal petal (cucullate) and ovary, but differs from the latter in having orange-red flowers, pale reddish orbicular lateral sepals, navicular lower sepal with abruptly constricted spur and dorsal petal with blunt horn. A detailed description along with colour photographs, and similarities with allied species are illustrated in detail are provided.

This study establishes two new species, Aspidistra tenuistyla and A. luteo-rubra (Asparagaceae, Convallarioideae). The first one, Aspidistra tenuistyla, is described here as a new species for science. It was discovered in the lowland limestone area of Ba Be National Park (Bac Kan Province). A detailed illustrated description of this species, along with data on its distribution, ecology, and phenology, is provided. According to the criteria of the IUCN Red List, the conservation status of A. tenuistyla is estimated as Near Threatened (NT). Additionally, the species rank is proposed for A. luteo-rubra, the plant regarded earlier as a variety (A. lutea var. luteo-rubra). It was found in the limestone area of Ngoc Son-Ngo Luong Nature Reserve (Hoa Binh Province). Both plants belong to the group of species with narrowly tubular flowers and are most closely related to A. lutea. A detailed, illustrated comparison of A. tenuistyla, A. lutea, and A. luteo-rubra is additionally presented. All these species are endemic to the limestone regions of northern Vietnam.

Thàn mát (Millettia nigrescens Gagn.), một loài cây bản địa đặc trưng của Bán đảo Sơn Trà, thành phố Đà Nẵng. Cây thường xanh, hoa và dáng đẹp, đáp ứng tiêu chí cây xanh đô thị. Kết quả nghiên cứu kỹ thuật nhân giống hữu tính cây Thàn mát thu được như sau: Ngâm hạt Thàn mát trong dung dịch GA3 50 ppm (8 giờ) cho tỷ lệ nảy mầm cao nhất (92,7%). Ở giai đoạn vườn ươm đến thời điểm cây 8 tháng tuổi, công thức ruột bầu (88% đất mặt + 10% phân chuồng hoai + 2% supe lân) giúp cây con sinh trưởng cây tốt nhất với chiều cao trung bình đạt 80,8 cm và đường kính gốc trung bình đạt 0,79 cm. Che sáng 50% cây con có tỷ lệ sống cao nhất (91,7%) và sinh trưởng tốt nhất (chiều cao trung bình đạt 76,5 cm và đường kính gốc trung bình đạt 0,73 cm). Kết quả trồng thử nghiệm sau 12 tháng tại quận Sơn Trà cho thấy cây (24 tháng tuổi) có khả năng thích nghi tốt với môi trường đô thị, tỷ lệ sống cao (96,0%), sinh trưởng tốt (chiều cao trung bình đạt 216,6 cm, đường kính tán trung bình đạt 172,1 cm và đường kính gốc trung bình đạt 3,11 cm) và tốc độ tăng trưởng nhanh (chiều cao trung bình là 100,4 cm/năm, đường kính tán trung bình là 102,9 cm/năm và đường kính gốc trung bình là 2,03 cm/năm). Những kết quả này cho thấy cây Thàn mát bản địa có khả năng di thực trồng công viên, đường phố trên địa bàn quận Sơn Trà, thành phố Đà Nẵng.

A new species of Begonia (Begoniaceae), B. dakrongensis, from Central Vietnam is described and illustrated. B. dakrongensis resembles B. abbreviata in its rhizomatous habit, short cymose-paniculate inflorescence with congested bracts, 4-tepaled staminate flowers, and 5-tepaled pistillate flowers. However, the new species markedly differs by having obtriangular-spathulate to oblong-obovate or widely obovate lamina (vs. ovate to broadly ovate), not oblique or nearly so (vs. oblique), widely obovate anthers (vs. narrowly obovate), and trigonous-globose ovary (vs. trigonous-ellipsoid).

Dendrobium namdongense is described here as a new species from limestone areas of the Nam Dong Conservation Area, Thanh Hoa Province, Quan Hoa District (northern Vietnam). This species inhabits primary evergreen broad-leaved and mixed forests on karstic limestone at elevations of 900–1100 m a.s.l. in a zone of humid, cool tropical climate. A detailed illustrated description and comparison of the discovered plant with the morphologically closest species, D. fuscifaucium and D. hekouense is provided, along with data on its distribution, ecology, and phenology. The new species has a potential in ornamental horticulture. According to the criteria of the IUCN Red List, the conservation status of the species is determined as Critically Endangered (CR).

The paper provides an identification key and an annotated list of all six species of the genus Ridsdalea J.T.Pereira & K.M.Wong (Rubiaceae, Gardenieae) recorded in the flora of Vietnam, along with data on their valid names, synonyms, types, and distribution. A new species, R. backanensis, discovered in the limestone area of Bac Kan Province (northern Vietnam), is described and illustrated. Detailed data on its characters, ecology, distribution, phenology, preliminary IUCN conservation status, and taxonomical notes are given. The newly discovered species is potentially interesting for cultivation as an ornamental tree that may be effectively used in garden and urban green architecture.

The detailed floristic inventory of Nam Dong Conservation Area was undertaken during 2015-2021. For the survey, 11 plots were established and studied. Herbarium specimens for almost all observed plant species were collected in the studied area. They were used for identifications and documentation of plants cited in in this report. The study pays special attention to vascular plants notable for their high number of endemic and rare species in limestone karst ecosystems typical for Nam Dong Conservation Area. The results of our preliminary botanical survey, indicate that Nam Dong Conservation Area supports a rich and very diverse flora. The survey reports 1312 vascular plant species in 637 genera belonging to 180 families. May of recorded species are rare and narrowly endemic plants. Among them 2 taxa new for science, and 1 represents new record for the flora of Vietnam. Aside from the high plant diversity, the Nam Dong forests contain many economically important plants, widely used by local communities. Such species groups include numerous timber trees, medicinal, ornamental and edible plants.