Pueraria bella Prain (1898: 288)

Jiang, Kai-Wen, Tian, Bin & Pan, Bo, 2022, Legume additions to the flora of China, Phytotaxa 532 (1), pp. 1-21 : 13-15

. Pueraria bella Prain (1898: 288) .

Type:— MYANMAR: Kachin, mountains near Myitkyina, King’s collectors (Shaik Mokim) s. n. (holotype CAL, isotypes CAL, K). Fig. 7.

Description: —Woody climbers, ca. 10 m. Old stems quadrangular, 10 cm across or more; young branches terete, nearly glabrous or somewhat pubescent. Leaves pinnately trifoliolate; stipules linear, dorsifixed, caducous; petiole ribbed, grooved above, nearly glabrous, (6–) 7–13 cm, with rachis (1.5–) 2–3 cm; leaflets long elliptic with lateral ones conspicuously oblique, (8–)13–18 × 3.5–8 cm, long-acuminate at apex, broadly cuneate to rounded-cuneate at base, sparsely pubescent on both surfaces, lateral veins 5–7 pairs, prominent below; petiolules 5–6 mm; stipels subequal to petiolules. Inflorescence an axillary pseudoraceme, unbranched or with one branch, 22–29 cm, rachis obviously nodose, 3 flowers per node; bracts 4 per node; bracteoles 2 per flower, caducous, broadly ovate, ca. 2 × 2 mm, striate, short-hairy on both surfaces, obtuse to acute at apex. Pedicel ca. 6 mm. Calyx campanulate, short velvety pubescent on both surfaces; tube 4–6 mm; lobes 4, obtuse, 3–4 mm, nearly equal in length, the upper lobe slightly emarginate at apex, the lower one more acute than other lobes. Corolla bicolored; standard orbicular-ovate, white to light purple, with a yellow patch and purple ring at the center, 14–17 × 11 mm, emarginate at apex, auriculate, with a short claw ca. 2 mm; wing petals oblanceolate, bluish purple, ca. 18 mm, with a basal claw ca. 5 mm, auricle incurved, ca. 2.5 mm; keel petals oblong, white to light purple, ca. 18 mm, with a basal claw ca. 5 mm, auricle obscure. Stamens monadelphous, ca. 18 mm; with vexillary one fused with staminal sheath only in the middle part; anthers uniform, basifixed. Ovary elongate, shortly adpressed pubescent, ca. 16 mm; style short, upcurved, ca. 3 mm; stigma capitate. Pod oblong, 3.5–8× 1.5 cm, flat, glabrous, winged along both sutures. Seeds reniform.

Distribution and habitat: — Pueraria bella is distributed in China (Yunnan Province), India and Myanmar. It grows in tropical montane forests at elevations between 200–1000 m above sea level.

Phenology: —Flowering in July to September; fruiting in October to December.

Chinese name: —The Chinese name of Pueraria bella is here given as 双ḏƀ, in which “ 双ḏ ” refers to the wings along both sutures of the pods, while “ ƀ ” is the Chinese common name for Pueraria . The pod is described for the first time, and is unique among all the Pueraria species.

Conservation status: —When revised Pueraria, van der Maesen (1985) only traced four gatherings collected from India and Myanmar. In the present work, we traced four more gatherings collected from China and Myanmar. As stated by van der Maesen (1985), P. bella is rare, and the number of known gatherings is still very small. Following IUCN (2019), here we consider the conservation status of P. bella is Vulnerable [VU, C a(i)].

Specimens examined:— CHINA. Yunnan: Luxi, Xuangang to Jiangdong, roadside, alt. 1089 m, 17 th Jul. 2013, H. J. Dong, Z. H. Wang, G. X. Hu & Y. P. Chen LX-Z-251 (KUN). Ruili, Longchuan River, 14 th Feb. 2011, S. S. Zhou 11389 (HITBC). Yingjiang, Geduo, alt. 980 m, 29 th Aug. 1980, Anonymous collector 319 (SWFC). MYANMAR. Tenasserim Division: Tavoy District, Area within a radius of 12 miles from Paungdaw, alt. 800 ft., Oct. 1961, J. Keenan, U. T. Aung and R. H. Rule 1818 (A).

Discussion: — Wu (1995) recognized eight species and two varieties of the genus Pueraria in China, while Wu & Thulin (2010) recognized ten species and two varieties in China. However, the molecular phylogenetic study by Egan et al. (2016) showed that Pueraria s. lat. is polyphyletic, and thus the taxa with basifixed stipules were transferred to Haymondia A. N. Egan & B. Pan bis (2015: 212), Neustanthus Bentham (1852: 234) , Teyleria Backer (1939: 107) , and Toxicopueraria A. N. Egan & B. Pan bis (2015: 214) by Egan & Pan (2015). Together with Pan et al. (2015) and the present study, there are eight species and two varieties of Pueraria s. str. distributed in China. An updated key is given below.