Po-Po Wu

Impatiens nushanensis (Balsaminaceae), a new species from Yunnan, China, is described and illustrated here. The new species is morphologically most similar to I. purpurea, but differs by having two pairs of lateral sepals and deep purple lower lobe of the lateral united petal with an acuminate and ribbon-like apex. Furthermore, phylogenetic analysis based on molecular data also support the recognization of this new species.

Yarlung Zangbo Grand Canyon National Nature Reserve has the most complete vertical vegetation belts in China. However, identification and distribution of vertical vegetation belts is still uncertain and in debate. To explore the above issues, 190 plots were surveyed within the reserve from 2019 to 2021. Based on the vegetation plot data, cluster analysis, ordination analysis, and biodiversity statistics were performed to reveal the structure of vertical vegetation belts–the driving factors of vegetation distribution–to describe the main biodiversity patterns. Five vertical vegetation belts were identified by clustering. NMDS ordination showed that the main factor of vegetation distribution is elevation. Based on the results of the analysis and previous literature, a new scheme of vertical vegetation belts in the south slope of the reserve was proposed. There was a lower montane seasonal rainforest belt (600–1100 m), a lower montane evergreen broadleaf forest belt (1100–1800 m), a middle montane semi-evergreen broadleaf forest belt (1800–2400 m), a subalpine evergreen needleleaf forest belt (2400–3800 m), a alpine shrubland and meadow belt (3800–4400 m), an alpine sparse vegetation belt (4400–4800 m), and a nival belt (4800–7782 m). Among them, the seasonal rainforest belts are the northernmost distribution of this type, and the semi-evergreen broadleaf forest belts exist only in the Eastern Himalayas. The study showed a unimodal pattern in plant species diversity, the peak of which is about 1900 m. The middle montane semi-evergreen broadleaf forest belt had the highest species diversity in the reserve. This study settled the issues regarding the vertical vegetation belts, the main drivers of vegetation and assessment of plant species diversity in the south slope of the Yarlung Zangbo Grand Canyon National Nature Reserve. It provides essential support for the management and conservation of these ecosystems in the reserve.

Calanthe × yarlungzangboensis P. P. Wu & Z. Wang, a new natural hybrid was described and illustrated from Xizang, China. Calanthe griffithii and C. tricarinata were considered as putative parentage by morphological traits and molecular data from nrITS and two plastid DNA (rbcL and matK). Calanthe × yarlungzangboensis is easily distinguished from its parentage by mid-lobe with three tuberculatus lamellae. The new hybrid grows in subalpine evergreen coniferous forest dominated by Tsuga dumosa in the eastern Himalayas with elevation about 2500m.