Astragalus wulingensis Jia X. Li & X. L. Yu, 2014

Li, Jiaxiang & Yu, Xunlin, 2014, Astragalus wulingensis (Leguminosae), a new species from Hunan China, Phytotaxa 159 (4), pp. 279-286 : 280-282

Astragalus wulingensis Jia X. Li & X. L. Yu , sp. nov. ( FIGURE 1 )

Differs from Astragalus sinicus by: Leaflet 1.5–2.8 × 0.8–1.1 cm wide, flower white, drooping, inflorescence shorter than leaf, calyx lobes linear, ca.1/1 tube length, claw of wing and keel-petal ca. 1/1 limb length, pod 3–4cm long with beak ca. 1 cm long.

Type: — CHINA. Hunan: Taoyuan county , beside mountain path, elevation ca. 190 m, 28 o 52’1.7’’ N , 111 o 1’41.22’’ E, 26 April 2013 , X. L. Yu 13017 (holotype, CSFI!; isotypes, CSFI!, PE!) .

Biennial herbs, 30–50 cm high. Roots whitish. Stem procumbent or ascending, sulcate-angular, more or less darkreddish, zigzag branched, sparsely appressed white hairs, 30–40 cm long, internode 4.5–12 cm long. Leaves imparipinnate, 10–17 cm long; stipules free, membranous, triangular, 5–8 × 2–4 mm abaxially puberulent at the edge, adaxially glabrous; petiole 3–5 cm long; rachises more or less dark-reddish, sulcate-angular, sparsely hairs; nodes swelling slightly; leaflets in 4-pairs, rarely 3- or 5-pairs, ovate, 1.5–2.8 × 0.8–1.1 cm, apex obtuse or mucronulate, base suborbicular or cuneate, abaxially with appressed white hairs when young and gradually becoming sparse or glabrous, adaxially with white dense hairs when yong and gradually becoming glabrous; Axillary raceme with densely clustered flowers at the apex, 6–10-flowered, shorter than leaves; peduncles slender, 4–10.5 cm long, sparsely white appressed pubescent; bracteoles trianglular-lanceolate, 1 × 1 mm, with dense appressed short white hairs; pedicels 2–3 mm long, with sparse short white hairs. Calyx tubular, ca. 7 mm long, adaxially glabrous, abaxially covered with sparse short white hairs which are also found along the lobes; lobes linear, 3–4 mm long, equal with or slightly longer than the tube. Flower 13–17 mm long, 5–8 mm wide, drooping; petals white, apically light purple; standard obovate, 11–14 mm long, 5–8 mm wide, apex emarginate, base attenuate, claw 2–3 mm long, limb 9–11mm long with upper reflected and lower tubular; wings oblong, 10–13 mm long, 2–3mm wide, claws 5–7 mm long, limbs 5–7 mm long, auricles ca. 2 mm long; keel-petals 7–15 mm long, 2– 3mm wide, claws 4–6 mm long, limbs 4–6 mm long, auricles ca. 3 mm long; stamens diadelphous, with (9) + 1, filaments 1–1.4 cm long, apex curved; ovary linear-elliptic, ca. 1 cm long, glabrous, stipe 2–3mm, 1 locule with 8– 11 ovules. Pods curved, calyx persistent, extending along dorsal suture, 3–4cm long, beak ca. 1 cm long; fruit stalk upright.

Distribution:— Endemic to Wuling Mountain, China and found from three localities: Guanyinsi, Taoyuan county (N28 o 52’1.7’’, E111 o 1’41.22’’), Wudaoshui, Sangzhi county (N29 o 42’43.92’’, E109 o 54’58.04’’) and Hupingshan, Shimen county(N29 o 57’0.27’’, E110 o 45’45.32’’) ( FIGURE 2 ).

Ecology & habitat:— Grows on mainly in mountain valleys in broad-leaf forest, beside rivers and the mountain paths at elevations between 150 and 300 m. Its habitat is shared with several perennial herbs [eg. Lysimachia christinae Hance (1873: 167) , Potentilla kleiniana Wright & Arnott (1834: 300) , Viola inconspicua Blume (1823: 57) ], annual herbs [eg. Corydalis racemosa ( Thunberg 1801: 103) Persoon (1806: 207) , Myosoton aquaticum ( Linnaeus 1753: 439) Moench (1794: 225) , Veronica henryi Yamazaki (1956: 296) , Clinopodium gracile ( Bentham 1848: 232) Matsumura (1904: 538) ] and few shrubs such as Oreocnide frutescens ( Thunberg 1784: 70) Miquel (1867: 131) .

Etymology:— This species is named for its locality, Wuling Mountain, China.

Phenology:— Flowering from April to May, fruiting from May to June.

IUCN Red List Category:— Astragalus wulingensis is only known presently from three localities on Wuling Mountain, North-west of Hunan, China ( FIGURE 2 ). Its habitat is vulnerable and is subject to destruction through human activities, particularly as it, grows beside rivers and paths. Moreover, there are fewer than 50 individuals in each of the three populations. Considering that the new species is circumscribed only to the small region of Wuling Mountain and that habitat fragmentation and gazing may significantly reduce the number of individuals. Therefore, according to IUCN Red List Criteria (2010), the new taxon should be regarded as Critically Endangered (CR B2c).

Similar species:— Astragalus wulingensis is included in section Lotidium Bunge year: page) of subgenus Astragalus Bunge (year: page) due to its stems and imparipinnate leaves with simple hairs, stigma glabrous, racemose inflorescence with densely clustered flowers at the apex, stipules free, stamens non-adnate with the base of petals, pods leathery. It is morphologically close to Astragalus sinicus , with shared characters of habit a biennial herb, with imparipinnate leaves, and racemose inflorescence. However, there are definitely many morphological differences from Astragalus sinicus , which are provided in TABLE 1, FIGURE 3 .

Figures

FIGURE 1. Astragalus wulingensis sp. nov.: (a) leaflets, (b) stipules, (c) flowering and fruiting plant, (d) infloresence with drooping white flowers, (e) pods, (f) calyx, (g) standard, (h) wing, (i) keel-petal, (j) pistil, (K) stamens. Scale bars: (a)= 10 mm, (b)= 5 mm, (c)=10 mm, (d)= 10 mm, (e)= 10 mm, (f)= 10 mm, (g)= 1.5 mm, (h)=1.3 mm, (i)= 1.7mm, (j)= 10 mm, (k)= 1.2 mm.

FIGURE 2. Distribution map of Astragalus wulingensis (●) in Hunan, China based on type specimens, photos by X. L. Yu’s photos from Sangzhi county, Wudaoshui, elevation ca. 250 m, 1 May 2005 and Jing Tian’s photos from Shimen county, Mt. Hupingshan, elevation ca. 200 m, 5 June 2010.

FIGURE 3. Morphological comparison between Astragalus wulingensis (A1–A6) and A. sinicus (B1–B6) based on flower. Legends: (A1,B1) calyx; (A2, B2) standard; (A3, B3) swing; (A4, B4) keel-petal; (A5, B5) pistil; (A6, B6) stamens. Scale bar: 5mm.