Millettia cubittii Dunn (1912: 188)

Song, Zhu-Qiu, Li, Shi-Jin, Vu, Quang Nam & Khang, Nguyen Sinh, 2022, Taxonomic notes on the genus Millettia (Fabaceae: Millettieae) in Vietnam, Phytotaxa 571 (2), pp. 169-185 : 173

1. Millettia cubittii Dunn (1912: 188)

Type: — MYANMAR. Bhamo , July 1909, G. E. S. Cubitt 226 (lectotype: P02141788 image!, designated by Lôc & Vidal 2001: 142; isolectotypes: K001415692 !, L0064652 image!) .

= Millettia setigera Dunn (1912: 188) . Type: — VIETNAM. Tonkin, Base du Mont Bavi, près de Tu-Phop, 28 June 1888, B. Balansa 2238 (lectotype: P02141866 image!, designated by Lôc & Vidal 2001: 130; isolectotypes: BM!, K000848748!, P02141867 image!), syn. nov.

Millettia cubittii and M. setigera were published at same time. The former species was based on five collections from Myanmar (G. E. S. Cubitt 226, J. H. Lace 5730, Fig. 1A, C. B . Smales s.n. and H. Collett 620) and China (A. Henry 10939, Fig. 1B ), and the latter was based on two gatherings (B. Balansa 2238, 2239, Fig. 1C–D ) from Tonkin, Vietnam. In the protologues, both species were placed by Dunn (1912) close to each other within the Sect. Otosema ( Bentham 1852: 248) Taubert (1894: 271) , but the key to species ( Dunn 1912: 142) indicated that they can be distinguished by features of the stipules, i.e. persistent in M. setigera and caducous in M. cubittii . In the Latin description, however, no significant differences were found in the description of the stipules: “stipulae lineares, persistentes” in M. cubittii and “stipulae aciculares, 4–5 mm longae, persistentes” in M. setigera ( Dunn 1912) . Lôc & Vidal (2001) also considered that both species are different in the length and growth pattern of the stipules, and described M. setigera with 6–8 mm long stipules in a brush-like pattern at the top of branches and M. cubittii with 2–3 mm long stipules not forming a brush. But in many references, M. cubittii was described also with about 8 mm long and persistent stipules ( Wei 1994, Sun 2006, Wei & Pedley 2010). In fact, a fruiting type specimen of M. cubittii was clearly shown to have 6–8 mm long and persistent stipules ( Fig. 1B ), which is very similar to the stipules in a fruiting type specimen of M. setigera ( Fig. 1D ). Based on the examination of literature and specimens as well as field observations, we concluded that M. cubittii and M. setigera represent the same species. We adopt M. cubittii as the correct name of the species due to its broader use (e.g. about 2120 results for “ Millettia cubittii ” while about 141 for “ Millettia setigera ” in google search). This species is characterised by its tree habit, evident leaf scars, persistent stipules (often in brush-like form at the top of branches during the fruiting period), stipellate leaflets, up to 2 cm long brachyblasts in the lower part of inflorescences, up to 2.0– 2.5 cm long flowers, a standard with two basal callosities, and brown hairy pods ( Fig. 2 ).

Figures

FIGURE 1. Millettia cubittii Dunn. A. syntype of M. cubittii (J. H. Lace 5730, K000848718, http://specimens.kew.org/herbarium/ K000848718); B. syntype of M. cubittii (A. Henry 10939, NY00016338); C. isolectotype of M. setigera Dunn (B. Balansa 2238, K000848748, http://specimens.kew.org/herbarium/K000848748); D. syntype of M. setigera (B. Balansa 2239, P02753644, https://science. mnhn.fr/institution/mnhn/collection/p/item/p02753644). A & C ©copyright of the Board of Trustees of the Royal Botanic Gardens, Kew; B ©copyright of the C. V. Starr Virtual Herbarium, New York Botanical Garden; D ©copyright of Muséum national d’Histoire naturelle.

FIGURE 2. Millettia cubittii Dunn. A. fruiting branches; B. branch apex during the flowering period, showing the morphology of stipules; C. branch apex during the fruiting period, showing the morphology of stipules; D. flowering branches; E. flowers; F. inflorescences, showing the distinct brachyblasts, scale bar = 2 cm; G. dissection of flowers, scale bar = 1 cm; H. mature fruits, scale bar = 2 cm; I. seed, scale bar = 1 cm. Vouchers: A (Zhu-Qiu Song 202030, IBSC), C & H–I (Zhu-Qiu Song 2021009, IBSC), and B & D–G (Zhu-Qiu Song 2021035, IBSC). Photos by Zhu-Qiu Song.