Cheilocostus tonkinensis (Gagnep.) Skornick ., 2022

Leong-Skornickova, Jana, Boehmova, Alzbeta & Tr ần, H ữu Đăng, 2022, A new species and new combination in basally flowering Vietnam Costaceae, PhytoKeys 190, pp. 103-111 : 103

Cheilocostus tonkinensis (Gagnep.) Skornick. comb. nov.

Figure 1B

Costus tonkinensis Gagnep., Bull. Soc. Bot. France 49: 248. 1903 [1902 publ. 1903], Type: VIETNAM, Mount Ba Vì, Balansa s.n., October 1887 (lectotype P! [P00686610], here designated).

Notes.

The type locality of Cheilocostus tonkinensis is in northern Vietnam, Mount Ba Vì. In the protologue, Gagnepain (1902) refers to two collections made by Balansa from this locality. There are four sheets at P: a single sheet of Balansa s.n., collected on 24 July 1886 [P00686610 - inflorescences & flower] and three sheets of Balansa 4206 collected in October 1887 [P02198384 - leafy shoot & single fruit; P02198381-inflorescence only; P02198385-leafy shoot only]. Both of these collections predate the protologue and are annotated in Gagnepain’s hand as published in Bull. Bot Soc. France 49: 248. All four sheets have to be considered as syntypes and, therefore, the lectotypification is needed. Unfortunately, none of the specimens consists of both leafy shoot and an inflorescence. Balansa s.n. [P00686610] with inflorescence and a flower, accompanied by a pencil drawing, is selected here as the lectotype.

It is challenging to distinguish Asian radically flowering Costaceae in herbarium material as the flowers do not preserve well. Based on our observations of living flowering material and photographic records with location data, Cheilocostus tonkinensis , so far, occurs in S. China, northern and central Vietnam and northern Laos, but may possibly extend to Thailand.

Figures

Figure 1. A Cheilocostus globosus, Singapore B Cheilocostus tonkinensis (Gagnep.) Skornick., Vietnam, photographed at the type locality. Photo by Jana Leong-Skornickova.