Jiangyou gentian (Metagentiana jiangyouensis) growing on cliff at elevation of 1160-1513 meters

NEWS - Jiangyou gentian (Metagentiana jiangyouensis) in Gentianaceae is known only from the type locality in Hanzeng Town, Jiangyou, Mianyang, Sichuan, China, growing on a cliff at an elevation of 1160-1513 m, flowering and fruiting from December to April with the local name jiang you xia rui long (江油狭蕊龙胆).

Metagentiana T.N.Ho & S.W.Liu was separated from Gentiana L. based on morphology and cytology which included 14 species. The genus is monophyletic when excluding two yellow-flowered species, M. souliei (Franch.) T.N.Ho, S.W.Liu & Shi L.Chen and M. striata (Maxim.) T.N.Ho, S.W.Liu & Shi L.Chen which were transferred to the new genus Sinogentiana Adr.Favre & Y.M.Yuan.

Morphological and molecular evidence suggests that Metagentiana is closely related to Sinogentiana, Tripterospermum Blume and Crawfurdia Wall. Metagentiana contains 12 species of which 9 are in southwest China, one is widespread in northwest and central China, one is distributed in eastern Myanmar and one is endemic to Thailand.

M. jiangyouensis is similar to M. villifera and M. rhodantha in perennial habit, presence of basal rosette, leaves and flowers. These three are the only Chinese species of the genus to have a basal rosette and can therefore be easily distinguished from all other Chinese species.

M. jiangyouensis differs from these two in that it is entirely glabrous, the calyx lobes are angular to lanceolate 1.3-2(-3) mm long, the corolla tube has dark purple spots and the margins of the plicae are not fringed. The basal rosette and vegetative shoots are short and well developed.

M. villifera and M. rhodantha sometimes have basal rosette leaves or vegetative shoots, but these are usually poorly developed or the vegetative shoots will grow into longer stems later. The other species are annuals or biennials without rosettes.

M. jiangyouensis differs from M. rhodantha also by seeds with narrow wings along the edge (vs. M. rhodantha with broad wings). M. jiangyouensis and M. villifera grow on rock surfaces (vs. M. rhodantha grows in grasslands, alpine shrubs, forests and on rocks).

M. jiangyouensis grows in Jiangyou at elevations of 1160-1513 meters (vs. M. villifera in Junlian or more than 420 km from Jiangyou at elevations of 800 meters; M. rhodantha is widespread in southwest, northwest, central and southern China at elevations of 500-1800 meters). Flowering and fruiting phase of M. jiangyouensis December-April, (vs. M. villifera April-June; M. rhodantha October-February).

Original research

Cao H-F, Cai J, Zou Y, Sun H, Li F-F, Xiong A-d, Xu M-J (2024) Metagentiana jiangyouensis, a new species of Metagentiana (Gentianaceae) from Sichuan, China. PhytoKeys 247: 137-144, DOI:10.3897/phytokeys.247.129934

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