Crotalaria humifusa Graham ex Bentham (1843: 476)

Ninkaew, Sakuntala, Balslev, Henrik, Pornpongrungrueng, Pimwadee & Chantaranothai, Pranom, 2017, Crotalaria L. (Fabaceae: Faboideae) in continental Southeast Asia, Phytotaxa 320 (1), pp. 448-450 : 448-450

16. Crotalaria humifusa Graham ex Bentham (1843: 476) . Type (lectotype designated by Ansari 2008):— NEPAL. Himalaya, 1821, Wallich 5421 (lectotype CAL n.v., isolectotypes K001120851!, 000633875!, K000633876!; K-W K001120851!). ( Figure 29 ).

Herb, prostrate, 10–25 cm high; young branches terete, brown pilose. Leaves simple. Stipules narrowly linear, 1– 2.5 mm long, deflexed, brown pilose, persistent. Petioles 0.5–1(–3) mm long, brown puberulous. Lamina obovate, oblanceolate or elliptic, 0.5–3.4 × 0.3–1.7 cm, base cuneate or obtuse, apex rounded, margin entire, both surfaces brown puberulous; lateral veins inconspicuous. Inflorescences axillary or leaf-opposed, open racemes, 2.5–15.2 cm long; peduncle 2.1–9.2 cm long, brown puberulous. Bracts narrowly linear, 0.5–1 mm long, persistent. Pedicels 1–3.8 mm long, brown pubescent. Bracteoles inserted on the calyx tube, narrowly linear, 0.5–1 mm long, caducous. Calyx 3–4 mm long, campanulate, bilabiate; tube 0.5–2 mm long; lobes triangular, 2–2.5 mm long, glabrous inside, brown pubescent outside. Corolla yellow. Standard: claw 0.3–0.5 mm long, glabrous; blade orbicular, 3–3.2 × 3.1–3.3 mm, base cuneate, apex obtuse or rounded, margin glabrous. Wings: claw ca. 0.2 mm long, glabrous; blade lanceolate, 2–2.2 × 1.6–1.8 mm, base oblique, apex obtuse, margin glabrous. Keel: claw ca. 0.2 mm long, glabrous; blade ovate, 3–3.2 × 1.6–1.8 mm, beak spirally twisted, base obtuse, apex attenuate, margin glabrous. Stamens: filaments fused for proximal 0.5–0.8 mm, free for distal 1.3–2.2 mm; anthers either narrowly linear, ca. 0.3 mm long or oblong, ca. 0.1 mm long. Ovary sessile, oblong, 2–2.3 mm long, glabrous; style 2.3–2.5 mm long with dispersed white pubescence. Pods sessile, oblong, 4–7 × 1.5–2 mm, brown, glabrous. Seeds reniform, 1.2–1.5 × 1–1.2 mm, brown.

Representative specimens: — THAILAND. Chiang Mai: Doi Chiang Dao Wildlife Sanctuary, Ban Khun Khong , 24 November 1989, Paisooksantivatana y2577-89 ( BK) ; Doi Inthanon National Park , 3 January 1975, Geesink et al. 8039 ( BKF) , 7 December 1984, Koyama & Phengklai T-40073 ( L) ; Hod , Ban Mae Sanam Mai, 14 November 2001, Sankamethawee 362 ( BKF) ; Mae Rim, Huai Puu , 19 December 2000, Glamwaewwong 7 ( QBG) . Mae Hong Son: Mueang , 29 October 2007, Maxwell 07-672 ( CMUB) . VIETNAM: Lai Chau: Phong Tho , 9 December 1937, Poilane 26776 ( K, L, P) .

Distribution: —Asia ( Nepal, China, Thailand, Vietnam), Australia. ( Figure 10 ).

Ecology: —Secondary grass-vegetation on granitic mountain slopes, partly shaded areas in fields, deciduous dipterocarp and pine forests, elevation 270–2550 m.

Notes: — Crotalaria humifusa is a new record for mainland Southeast Asia. All specimens belonging to this species were previously mis-identified as C. acicularis . These two species are similar in habit, but C. humifusa has distinctly narrowly linear stipules and bracts.

Figures

FIGURE 10. Distribution map of Crotalaria goreensis and C. humifusa in continental Southeast Asia.

FIGURE 29. Crotalaria humifusa:A) Habit; B) & C) Leaves; D) Flower; E) Calyx; F) Standard; G) Wings; H) Keel; I) Ovary; J) Anthers and K) Pod. Drawn by N. Triyuthachai from Koyama & Phengklai T-40073.