Annual dynamics of CO₂ fluxes from soils and the impact of the living activity of termites on them were studied in plain lagerstroemia semideciduous monsoon tropical forests of southern Vietnam. On the plot populated by Globitermes sulphureus and Odontotermes termites, a detailed study of the spatial heterogeneity of the CO₂ emission from the surface of soil and termite mounds was performed in the wet and dry seasons. It was found that the average rate of the CO₂ emission from termite mounds was two times and more higher than that from the background soil surface. In the dry season, it comprised 91 ± 7 mg C/m² per h from the background soil and 196 ± 16 mg C/m² per h from the termite mounds. In the wet season, the CO₂ emission rate was considerably higher and reached 266 ± 40 and 520 ± 39 mg C/m² per h, respectively. The maximum rates of CO₂ fluxes were determined in the wet season in some of the measurement chambers installed on termite mounds; they reached 730–880 mg C/m² per h. Though termite mounds occupy about 4% of the area of tropical forest ecosystems, the overall effect of termites on the carbon budget was more significant; according to our estimates, it reached up to 10% of the total efflux of CO₂ from the soil surface.

— Aspidistra cylindrica , a new species from southern Vietnam (Kon Tum province), is described and illustrated. The new species possesses a unique combination of cylindrical shape of pistil and shoot system with foliage leaves crowded in groups and not divided into petiole and lamina. Aspidistra cylindrica resembles A. muricata but differs in longer leaves, shorter and wider perigone, shorter pistil, shape and colour of perigone lobes, anther position, and stigma shape. The conservation status of A. cylindrica is assessed. A key for species of Aspidistra in southern Vietnam is provided.

Aspidistra nikitensis is described and illustrated as a new species from Gia Lai province of Vietnam. The new species possesses linear leaves and trimerous flowers with a mushroom-shaped pistil. In these features, the new species is morphologically similar to A. hainanensis species complex but differs in its convex stigma with projections. In stigma structure, A. nikitensis resembles A. longanensis but differs in shape of leaves and flower merism.

Thismia mucronata, a new species of Thismiaceae, is described and illustrated. The species was discovered in 2013 during a botanical survey of a forest in the vicinity of Bao Loc town (Lam Dong province, Southern Vietnam). Thismia mucronata is characterised by vermiform roots and mitriform inner tepals. It differs from related species mainly by the short and appressed to each other appendages of inner tepals, which together resemble a short mucro, the narrow mitre without foveae, the almost horizontal annulus and the absence of interstaminal glands. A key to Vietnamese species of Thismia is provided.

The paper summarizes the knowledge on three Vietnamese species of Ericaceae. Craibiodendron yunnanense is newly documented for the flora of Vietnam. The presence of Lyonia villosa in the country is confirmed by specimen citation. We publish a new combination, Vaccinium glaucorubrum, to accommodate the taxon earlier known as Vaccinium gaultheriifolium var. glaucorubrum at species rank. We provide a detailed morphological description of V. glaucorubrum and revise the geographical distribution of this species. We review type material of V. glaucorubrum and designate the specimen at KUN (1208884) as a lectotype. We illustrate all three species with analytical photographs of the plants in the living state.

This study was carried out during the period 1989–2011. The following areas were included: Vietnam, Laos, Cambodia, Indonesia, and Malaysia. Primary tropical forest and anthropogenically transformed...