Svetlana P. Kuznetsova’s research while affiliated with Severtsov Institute of Ecology and Evolution and other places

Aspidistra tripartita, a new species of Asparagaceae, is described and illustrated. The species was discovered in 2019 in Son La Province, northern Vietnam. Aspidistra tripartita belongs to a group of species characterized by campanulate to cupulate perianth tube and deeply lobed stigma. The new species is readily distinguishable from the other species of this group by thick rhizome (more than 10.5 mm in diameter), long and narrow ensiform leaf blades (28-71.5 cm long and 2.6-3.1 cm wide), and stamens with supraconnectives.

Expeditionary studies of the functioning of landscapes of mid-mountain monsoon (including fog) forests have been being conducted within the landscape and ecological station in the territory of the Bidoup-Nui Ba National Park and the adjacent Hon Giao since 2018 and are currently underway. One of the research objectives is to clarify the biogeochemical migrations of the material composition of soils in the “leaf debris–soil” system. We have consistently studied natural objects for their material composition as well as the intensity and rate of involvement of chemical elements in physicochemical migration processes in the “leaf debris–soil” system. Our findings indicate an active influx of a select group of examined elements (Se, Pd, Ag, Cd, Sn, Bi), particularly Bi, Pd, Se, and Cd, through the leaf debris and the detachment of aboveground plant organs, warranting their integration into organogenic soil horizons. Subsequently, lateral migration (Pd, Cd, Se) ensues. Slope processes within subordinate landscape facets, in addition to soil moisture and aeration processes, contribute to the subsequent redistribution of elemental volumes introduced into organogenic soil horizons.

Thismia papillata, a new species of Thismiaceae, is described and illustrated. The species was discovered in 2023 in Thanh Hoa Province, northern Vietnam. The new species is readily distinguishable from most of its congeners by the presence of appendages of outer and inner tepals, inner tepals fused into a mitre, absence of a wing-like appendage of supraconnective and absence of interstaminal glands. Thismia papillata is similar to T. abei, T. taiwanensis and T. tuberculata, differing mainly in prominently papillate outer hypanthium surface, appendages of the outer tepals up to 15 mm long, appendages of the inner tepals up to 9 mm long, and column-like placentas. Gaps in understanding of interactions between the inner tepals in Thismia are highlighted that are related to the postgenital tepal fusion and tepal aestivation. Similar uncertainties in determination of fusion between the stamens are also uncovered.

A synopsis of the orchid genus Didymoplexiella is presented for Cambodia, Laos and Vietnam. Uncertainties in morphological delimitation of the species of Didymoplexiella are addressed in the context of the new data on variation of labellum structure; re-identification of a considerable number of specimens is performed in accordance with the current views. Three species are recognised in the study area. Of them, D. laosensis is endemic to Laos and Vietnam; D. ornata is known from Vietnam and also widely distributed in Malesia; and D. siamensis inhabits all three countries of Eastern Indochina and also Thailand, Japan, China and Taiwan. Didymoplexiella laosensis is newly recorded for Vietnam, whereas D. trichechus is excluded from the known flora of Eastern Indochina, and D. ornata is excluded from the flora of Laos. Typification of D. siamensis is revised. For each species, the type, synonyms (where applicable), citations of relevant regional taxonomic publications, brief taxonomic notes, data on ecology, phenology, distribution and IUCN preliminary assessment are provided. The geographical distribution of the species of Didymoplexiella in Cambodia, Laos and Vietnam is shown on a map. A key for the identification of D. laosensis, D. ornata, D. siamensis and D. trichechus is presented.

Meistera muriformis (Zingiberaceae: Alpinioideae), a new species from southern Vietnam is described and illustrated. The description is accompanied by additional notes on etymology, ecology and phenology, distribution, and preliminary IUCN assessment. Notes on differences from morphologically similar congeners are provided. The new species is diagnosed from its morphologically closest species, Meistera stephanocolea, by prominently reticulate leaf sheaths, open flower type and small anther crest with no prominent lobes. The novelty brings the total number of species of Meistera in Cambodia, Laos and Vietnam to 15. Morphological diversity and distribution of Meistera in these countries are briefly summarised, and an identification key is provided.

Peliosanthes linearifolia, a new species of Asparagaceae, is described and illustrated. The species was discovered in 2022 in Quang Nam Province, southern Vietnam. Peliosanthes linearifolia is remarkable for its linear to narrowly lanceolate leaves that are less than 1.3 cm wide. Such leaves were previously known only in P. graminea. Based on the floral characters of the new species, we assign it to the Peliosanthes teta species group. Peliosanthes linearifolia differs from P. teta, P. graminea and the other species of the group in the following combination of morphological traits: stoloniform rhizome, flowers solitary in axils of all primary bracts of inflorescence (i.e. inflorescence is a raceme), violet flowers and prominently lobed apex of the androecial corona.

Heliacria Bo Li, C.L. Xiang, T.S. Hoang & Nuraliev and H. maritima Bo Li, C.L. Xiang, T.S. Hoang & Nuraliev, a new genus and a new species of Scutellarioideae (Lamiaceae) endemic to coastal areas of south-central Vietnam, are described and illustrated. Heliacria is distinct from the other five genera of Scutellarioideae by having climbing habit, large flowers with pure white corolla, sub-actinomorphic calyx with five long lobes which are accrescent and spreading in fruits, and nutlets radially tuberculate at apex. The genus is currently only known from four provinces of Vietnam (Binh Dinh, Phu Yen, Khanh Hoa, and Ninh Thuan).

Mitreola capitata, a new species of Loganiaceae, is described and illustrated. The species was discovered in 2022 during a botanical survey of Phong Nha-Ke Bang National Park (Quang Binh Province, northern Vietnam), where it inhabits a steep limestone rock. Mitreola capitata is remarkable for its habit that includes a leaf-rosette, compact head-like inflorescence with long peduncle and prominent indumentum of most plant parts. The new species is most similar to M. spathulifolia, differing by smaller leaves, dense and compact inflorescence, shorter pedicel, hairy calyx and smaller capsule. Typification of M. spathulifolia is revised, and a lectotype is selected.