Mucuna pruriens De Candolle 1825
Creators: name: Jiang, Kai-Wen
name: Tian, Bin
name: Pan, Bo
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Mucuna
Mucuna pruriens

description: . Mucuna pruriens (Linnaeus 1754: 23) De Candolle (1825a: 405)  var. hirsuta  (Wight & Arn.) Wilmot-Dear (1987: 44).   
 Mucuna hirsuta Wight & Arnott (1834b: 254). Mucuna pruriens (L.) DC. f. hirsuta (Wight & Arn.) Backer (1963: 629). Stizolobium hirsutum (Wight & Arn.) Kuntze (1891: 208).   
 Type:— INDIA. Peninsula India Orientalis, Wight 750 (holotype K000797547!, isotypes E00174529!, E00174530!). Fig. 5 & 6.   
 Mucuna pruriens var. thekkadiensis Thothathri & Ravi Kumar (1997: 703). Type:— INDIA. Kerala: Thekkady forest, Periyar Tiger Reserve, 23 rd Feb. 1996, Ravikumar & Muralidharan 535A (holotype MH!, isotypes MUH, CAL).   
 Mucuna incurvata Wilmot-Dear & R. Sa (2010: 218). syn. nov. Type:— CHINA. Yunnan, “Che Li Hsien, Ban-chiou Chian” [Jinghong County], mixed forest, alt. 840 m, Oct. 1936, C. W. Wang 79571 (holotype PE00414137!, isotypes A00195002!, PE00414136!, IBSC0154685!, KUN0618402!, LBG00091571!).   
 Description: —Herbaceous climbers. Stems glabrous or sparsely hirsute with spreading yellowish hairs, striate. Leaves trifoliolate; stipules caducous; petioles 5.5–11 cm, with a pulvinus ca. 0.5 cm at base, slightly grooved above, hirsute as stem but sometimes denser; leaflets chartaceous, dark green on the adaxial surface, sparsely covered with appressed white hairs when young, glabrescent when old, grey-green on the abaxial surface, densely covered with appressed white hairs throughout, sometimes yellow hairy along veins and margin, acute at apex, mucronate, slightly repand at margin, lateral veins (including basal veins) 5–6 pairs, terminal leaflets rhombic-ovate, 11.9–14 × 5.8–8.2 cm, laterals oblique, 8.9–11.8 × 4.5–7 cm; rachis 1.3–2.2 cm, hirsute as petiole; stipels ca. 0.3 cm, black, persistent, slightly shorter than petiolules; petiolules densely covered with yellowish hairs. Inflorescence an axillary or cauline pseudoraceme, 2– 3 flowers per node; peduncles and rachis appressed pubescent; bracts and bracteoles caducous: primary bract one per node, lanceolate narrowly-triangular, densely villous with ± ascending, pale hairs abaxially, pubescent with somewhat sparser brownish hairs adaxially; secondary bract one per flower, ± ovate, indumentum as on primary bracts; bracteoles two per flower, densely villous with ± ascending, pale hairs on both surfaces. Calyx bilabiate, covered with brownish irritant bristles and dense ± appressed grey hairs; the adaxial two lobes connate to form the upper lip, the other three lobes triangular, acute at apex. Corolla dark purple, turns black when dry; standard sub-elliptic, ca. 2.5 cm, with a short claw ca. 1.7 mm at base; wing petals long obovate, ca. 3.7 cm, densely covered with spreading grey hairs along the dorsal side of the basal part, with a short claw ca. 2.2 mm, auricle ca. 1 mm; keel petals ca. 3.8 cm, hooked at apex, sometimes “claw-like”, basal claw ca. 6.3 mm, auricle ca. 1 mm. Stamens 10, diadelphous (9+1), with vexillary one free from the staminal tube; ca. 4 cm; anthers dimorphic, alternative. Pistil shorter than stamens, ca. 2.7 cm, hirsute with spreading hairs. Pods fleshy, straight or slightly irregular bending, never curved into S shape, densely covered with yellowish taupe irritant hairs ca. 3 mm. Seed oblong-ellipsoid, ± compressed, dark brown with taupe and black spots, 1–1.1 × ca. 0.7 cm; hilum ca. 6 mm.   
 Distribution and habitat: — Mucuna pruriens var. hirsuta is distributed in China (South Guangxi and Yunnan, newly recorded, reported here), India (Western Indian Peninsula), Myanmar, Vietnam and Thailand. It grows on the edge of woods or roadsides at elevations between 100‒1650 m above sea level, usually climbing on trees.   
 Phenology: —Flowering in September to next January, fruiting in October to next April.   
 Chinese name: —The Chinese name of Mucuna pruriens var. hirsuta is given here as ą毛ḙā, in which “ ą毛 ” means “hirsute hairs”, which is the direct translation of the epithet; “ ḙā ” is the Chinese common name for Mucuna Adans. subg. Stizolobium (P. Browne 1756: 290) Baker (1876: 186).   
 Taxonomic notes: — Mucuna pruriens var. hirsuta is similar to var. pruriens in its inflorescence and flower parts, but can be easily distinguished by its straight or slightly irregular bending pods which are never curved into an S shape (vs. always curved into an S shape in var. pruriens); the indumentum on pods of the two varieties is different: var. hirsuta bears yellowish taupe irritant bristles, which turn to a greyish-black color when mature, var. pruriens bears orange-red orange-brown or yellow irritant hairs, which turn to a brown or greyish yellow color when mature. As for vegetative part, M. pruriens var. hirsuta can be easily characterized by the presence of yellowish hairs on leaflets and petiolules, which is different to those of var. pruriens. M. pruriens var. hirsuta is also easily confused with M. bracteata, another species of Mucuna subg. Stizolobium distributed in China, since both taxa bears straight or slightly irregular bending pods, however, the lower part of the inflorescence of M. bracteata bears many flowerless nodes with scars and persistent bracts, but bracts of M. pruriens var. hirsuta are completely caducous; moreover, the terminal leaflet of M. bracteata has its width similar to length, while both of M. pruriens var. hirsuta and var. pruriens have terminal leaflet usually longer than width; M. bracteata bears flowers with wing petals conspicuously shorter than keel petals, while both of M. pruriens var. hirsuta and var. pruriens bear flowers with wing petals subequal or slightly shorter than keel petals.   
 When she revised Chinese and Japanese Mucuna species, Wilmot-Dear (1984) recorded four doubtful taxa and named them temporarily and informally as Mucuna sp. ‘A’, ‘B’, ‘C’ and ‘D’, of which, only two gatherings of M. sp. ‘A’ were cited. Later, M. sp. ‘A’ was described formally as a new species, Mucuna incurvata Wilmot-Dear & R. Sa, in Flora of China by Sa & Wilmot-Dear (2010). The authors indicated this species resembles M. pruriens but differs in having lateral calyx lobes twice as long as wide, all calyx lobes much broader, corolla with a more incurved and claw-like keel, longer hairs on the stem and leaves adaxially, and much finer bristles on the calyx. We traced the digital image of the holotype and all isotypes of M. incurvata, as well as an illustration cited by Sa & Wilmot-Dear (2010), but we did not find the key morphological characteristics to distinguish M. incurvata from M. pruriens var. hirsuta. There is no obvious difference in the morphological characters of the calyx lobes and their indumentum between the two taxa; and the long hairs on the stem and adaxial surface of leaves also coincide with the morphological characters of M. pruriens var. hirsuta; the “claw-like” maybe represents an atypical form in the taxa. Based on these observations, here we synonymize M. incurvata with M. pruriens var. hirsuta.   
 Although Sa & Wilmot-Dear (2010) only cited two duplicates of C. W. Wang 79571 stored in A and PE as the isotypes of M. incurvata, we traced three more duplicates of C. W. Wang 79571 stored in IBSC, KUN and LBG. According to Art. 9.5 of the Shenzhen Code (Turland et al. 2018), these duplicates are also the isotypes of M. incurvata, as we cited above.   
 Wilmot-Dear (1987) considered M. pruriens var. hirsuta endemic to W Peninsular India. Wilmot-Dear (1992, 2008) traced more specimens and considered it also distributed in Vietnam and Thailand. In this study, we traced two more specimens collected from Vietnam and one specimen from Myanmar (see specimens cited below, also see Fig. 6), which suggests that this taxon has a much wider geographical range than previously thought.   
 Conservation status: — Mucuna pruriens var. hirsuta is a widespread taxon, so we consider it as Least Concern (LC) according to IUCN (2019).   
 Specimens examined:— CHINA. Guangxi: Napo, Bainan, Shanggai Village, mountainous areas, on slope, sparse forests, alt. 400 m, 11 th April 1998, H. N. Qin, Y. Z. Wang, L. C. Yan, X. Y. Wen, D. S. Deng, S. C. Tang, B. M. Nong, X. C. Zhang & N. H. Xia 398 (PE). Yunnan: Cangyuan, Banlao, Mt. Longtoushan, in the forest, alt. 850 m, 31 st Oct. 1989, G. D. Tao, X. W. Li 39993 (KUN). Che-li Hsien, Dah-meng-lung, Meng-song, mixed woods, alt. 1650 m, Sept. 1936, C. W. Wang 78220 (KUN, PE). Che-li Hsien, Kuen-ger, mixed forest, alt. 900 m, Oct. 1936, C. W. Wang 79233 (PE). Hekou, Mt. Jinjinashan, in thickets, moist place, alt. 100 m, 10 th Nov. 1954, K. M. Feng 5399 (KUN). Jenn-yeh Hsien, Meng-him, alt. 800 m, Oct. 1936, C. W. Wang 79947 (PE). Jinghong, Puwen, in the forest, climbing on trees, alt. 200–300 m, 3 rd Jan. 2014, X. X. Guo 1401 (CSH). Luchun, near Erqu, roadside at the edge of forests, alt. 450 m, 19 th Oct. 2000, Y.-M. Shui & W.-H. Chen 13405 (KUN). Mengla, edge of the rainforest valley, alt. 650 m, 16 th Oct. 1959, H. T. Tsai 59-13383 (KUN). Mengla, Longlin, in forest, alt. 750 m, 19 th Oct. 1959, H. T. Tsai 59-11028 (KUN). Mengla, Menglun, Xishuangbanna Tropical Botanical Garden, Scientific Research Center, roadside, climbing on trees, 9 th Jan. 2019, K. W. Jiang & B. Pan SSPN02 (CSH). ibid., 9 th Jan. 2019, K. W. Jiang & B. Pan SSPN03 (CSH). ibid., 9 th Jan. 2019, K. W. Jiang & B. Pan SSPN04 (CSH). ibid., 10 th Jan. 2019, K. W. Jiang SSPN13 (CSH). Mengla, Mengyuan, Nanyang Village, roadside, 5 Dec. 2004, S. S. Zhou 2173 (PE). Mengla, Mohan, mountainous area near Miaozhai Village, edge of forests, 29 th Nov. 2020, B. Liu, L. M. Lu, R. Rabarijaona, R. Liu 11708 (PE). Mengla, Shangyong, roadside, alt. 800–900 m, Z. H. Yang 10888 (KUN). Mengla to Shangyong, in thickets, alt. 580 m, 17 th Oct 1959, H. T. Tsai 59-10996 (KUN). Xishuangbanna, Manyan to Manliangsan, moist place, sunny place in the valley, roadside, in thickets, 6 th Nov. 1958, S. X. Zhao 174 (KUN). Yingjiang, from Tongbiguan to Rubber Plantation, 26 th Oct. 1983, Q. Lin 770793 (KUN). Yingjiang, Xianghubang River, in valley, Apr. 1979, Yunnan Institute of Botany 03- 14 (KUN). Yingjiang, Nabang, old road from Xima to Nabang, edge of forests, 18 th Dec. 2016, CPG Exped. 29347 (PE). Yingjiang, Taiping, Hongbeng River, riverside, 21 st Dec. 2016, CPG Exped. 29463 (PE). MYANMAR. Upper Burma, Kachin Hills, Mar. 1898, S. Mokim s. n. (L). VIETNAM. Lạng Sõn, Hữu Bồn(?) Farm, NW 32 km, Mt. Núi Ba Tầng(?), under the forest, alt. 190 m, 16 th Jan. 1965, China-Vietnam Joint Exped. 1441 (KUN, PE). Lào Cai, 8 km Nam Cýờng, secondary forest edge, on sunny slope, alt. 351 m, 18 th Dec. 1964, China-Vietnam Joint Exped. 532 (PE).   
 Discussion: — Sa & Wilmot-Dear (2010) recognized 18 species and one variety of the genus Mucuna distributed in China, together with Jiang et al. (2020) and present study, at least 18 species and two variety of Mucuna can be found in China. These taxa belong to three subgenera based on the treatment by Moura et al. (2016), i.e. Mucuna subg. Mucuna, M. subg. Macrocarpa T. M. Moura, Wilmot-Dear, M. Vatanparast, A. M. G. Azevedo & G. P. Lewis (2016: 610), and M. subg. Stizolobium. Two species and two varieties distributed in China should be placed in M. subg. Stizolobium. An updated key to the subgenus distributed in China is given below.
description: Published as part of Jiang, Kai-Wen, Tian, Bin & Pan, Bo, 2022, Legume additions to the flora of China, pp. 1-21 in Phytotaxa 532 (1) on pages 9-13, DOI: 10.11646/phytotaxa.532.1.1, http://zenodo.org/record/5900839