Abstract: Ligusticum is a highly specialized genus in the tribe Ammineae Koch of the subfamily Apioideae. It is transitional between the tribe Ammineae Koch and the tribe Peucedaneae DC., and shows a very close affinity to the genus Selinum. In the present paper, the taxonomic history is reviewed; the external morphology, pollen morphology and geographic distribution are analysed, and its evolutionary tendencies are discussed. In addition, a key to the 34 species is provided, and economic uses reported in the literature are summarized. Ligusticum consists of over 60 species widely distributed in Eurasia and North America; the genus is typically temperate. There are two principal distribution centers, one in the Himalayas, including the Hengduan Mountains of western China, and the other in North America. Thirty-four species occur in China, most of which are distributed in the alpine belt of south-western China, with only a few species occurring in northern China. They usually grow in alpine thicket meadows or in alpine meadows. Among them are 28 species endemic to China, 4 of which are described as new in the present paper, i. e. L.yuayuanense, L.litanense, L.filifolium, and L.yunnanense. L.elatum (Edgew.) C. B. Clarke, a species of India, Afghanistan, and Pakistan, and L. thomsonii C.B.Clarke var. evolutior C. B. Clarke, of India, Pakistan and Kashmir, are reported from China for the first time. Some species are important in traditional Chinese medicine, for example, L. sinense Oliv., L. sinense Oliv. cv. Chuanxiong, L. sinense Oliv. cv. Fuxiong, L. delavayi Franch., L. jeholense (Nakai et Kitagawa) Nakai et Kitagawa, L. tachiroei (Franch. et Sav.) Hiroe et Constance, etc. The genus Tilingia was established by Regel in 1858, based on Tilingia ajanensis. The chief characters of the genus are distinct calyx teeth and carpels bearing a solitary vitta in each furrow. However, these characters do not differentiate Tilingia from Ligusticum, so that Tilingia was transferred to Ligusticum by Kozo-Poljansky in 1916. Tilingia tachiroei (Franch. et Sav.) Kitagawa was transferred to Ligusticum by Hiroe et Constance in 1958. Shan et Sheh in “F1. Reip. Pop. Sin.” Tom. 55 supported the treatment by Kozo-Poljansky and Hiroe and Constance The genus Ligusticopsis was separated from Ligusticum by Leute in 1969, based on the prominent calyx teeth of the former. Ligusticopsis included 14 species, all confined to China. But this genus has not been accepted by any other botanists since its establishment. The subdivision of Ligusticum in this paper is based mainly on the characters of involucel bracteoles and mericarps, combined with the shape and aperture types of pollen grains. The genus is divided into the following two sections. Sect.1 Ligusticum, Bracteoles linear or lanceolate, entire; mericarps slightly lateral-compressed to slightly dorsal-compressed; vittae solitary to numerous in each furrow; leaf-segments ovate, lanceolate, or linear; pollen grains mainly rhomboidal or ellipsoidal; apertures gonitreme. Sect. 2 Pinnatibracteola Pu. Bracteoles 1-3-pinnatisect or 2-3-lobed at apex; mericarps dorsal-compressed; vittae usually numerous in each furrow; leaf-segments usually linear, rarely ovate or lanceolate; pollen grains rectangular, elongate-rhomboidal, or equatorially constricted; apertures mainly peritreme, rarely gonitreme or intermediate.

Key words: Umbelliferae, Ligusticum, China