Taxonomic revision of Chenopodiaceae in Himalaya and Tibet

Abstract

The composition of many Chenopodiaceae genera in different parts of Himalaya and Tibet has been insufficiently known or contradictory. A revision of the family in Himalaya including Bhutan, Nepal, parts of India (Himachal Pradesh, Jammu and Kashmir, Sikkim and Uttarakhand) and Tibet (Xizang, China) is presented for the first time. Altogether, 57 species from 20 genera are reported, including three species new to science (Agriophyllum tibeticum, Salsola austrotibetica and Salsola hartmannii). Atriplex centralasiatica, Corispermum dutreuilii and Salsola monoptera are identified as new records for India and Chenopodium pamiricum is recorded in China for the first time. Dysphania ambrosioides and Sympegma regelii are recorded for Xizang. The generic and species keys, species distributions (including maps) and taxonomic notes are provided. We indicate for the first time that the presence of short yellow hairs is the remarkable morphological characteristic of the genus Grubovia. Evident heterocarpy and heterospermy is found in Dysphania for the first time (Dysphania tibetica). Agriophyllum pungens, Atriplex crassifolia, Atriplex laciniata, Atriplex sagittata, Axyris amaranthoides, Axyris hybrida, Bassia indica, Corispermum korovinii, Dysphania schraderiana (=Chenopodium foetidum auct.), Halocharis violacea and Suaeda microsperma are excluded from the species list. Neobotrydium corniculatum is synonymised with Dysphania kitiae, Neobotrydium longii with Dysphania himalaica and Neobotrydium ornithopodum seems to be conspecific with Dysphania nepalensis. Corispermum ladakhianum is a new synonym of Corispermum tibeticum. Amaranthus diandrus is added to the synonyms of Acroglochin persicarioides, and Bassia fiedleri, previously considered as conspecific with Grubovia dasyphylla, is added to the synonymy of Bassia scoparia. Lectotypes of Anabasis glomerata (≡Halogeton glomeratus), Halogeton tibeticus (=Halogeton glomeratus), Amaranthus diandrus (=Acroglochin persicarioides), Chenopodium tibeticum (≡Dysphania tibetica), Corispermum dutreuilii, Corispermum falcatum, Corispermum lhasaense, Corispermum pamiricum var. pilocarpum (=Corispermum gelidum, syn. nov.), Corispermum tibeticum, Kochia indica (≡Bassia indica), Kochia odontoptera (≡Bassia odontoptera) and Salsola monoptera are selected. Out of 53 native elements, 42 are restricted in their distribution to Himalaya and Tibet at altitudes 2000-4500 m above sea level. The greatest taxonomic diversity of the Chenopodiaceae is represented in Jammu and Kashmir (India) and Xizang (China) with a continuous decrease in the number of species southwards.