Crotalaria larsenii Niyomdham (1978: 139)

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

22. Crotalaria larsenii Niyomdham (1978: 139) . Type:— THAILAND. Khon Kaen: Dong Lan Forest , 22 November 1958, SØrensen et al. 6108 (holotype C10012056 !, isotype BKF49446 !).

Herb, erect, 30–40(–50) cm high; young branches terete, brown pubescent. Leaves simple. Stipules minute, caducous. Petioles short or absent. Lamina obovate-oblong, 3–6.5 × 1–2 cm, base cuneate to subattenuate, apex rounded, margin entire, glabrous upper, glaucous lower; lateral veins 4–6 pairs. Inflorescences terminal, open racemes, 2–3 cm long and 1–2 flowers from the upper leaf-axils; peduncle 1.5–2 cm long, silvery pubescent. Bracts narrowly linear, 1.5–2 mm long persistent. Pedicels 2–4 mm long, silvery pubescent. Bracteoles inserted on the pedicel, 1–2 mm long, persistent. Calyx 6–7 mm long, campanulate, bilabiate; tube ca. 0.5 mm long; lobes triangular, 5.5–6.5 mm long, glabrous inside, silvery pubescent outside. Corolla light yellow. Standard: claw 0.8–1 mm long, glabrous, margin white tomentose; blade obovate, 6–6.5 × 4–5 mm, base truncate, apex acute, pubescent, margin glabrous. Wings: claw 1–1.2 mm long, glabrous; blade oblong, 4–5 × 1.8–2 mm, base oblique, apex obtuse, margin glabrous. Keel: claw 0.8–1 mm long, glabrous; blade ovate, 6–6.2 × 3–3.3 mm, beak spirally twisted, base cuneate, apex acute, margin white tomentose. Stamens: filaments fused for proximal 1.5–2 mm, free for distal 2–4 mm, glabrous; anthers either narrowly linear, 0.8–1 mm long or orbicular, 0.3–0.5 mm long, glabrous. Ovary sessile, oblong, 2–2.2 mm long, brown pubescent; style 5.5–6 mm long, adaxially white pubescent in a single line along the distal edge, abaxially glabrous. Pods sessile, oblong, 1.3–1.5 × 0.4–0.5 cm, brown, pilose. Seeds not seen.

Representative specimens: — THAILAND. Sakon Nakhon: Phu Phan National Park , 8 August 1999, Leeratiwong 99-154 ( KKU) .

Distribution: —Asia ( Thailand). ( Figure 13 ).

Ecology: —Open areas in deciduous dipterocarp forests, elevation 300–1040 m.

Notes: — Crotalaria larsenii is recognized by its distinctive pilose pods, short or absent petioles and short inflorescences.

Figures

FIGURE 13. Distribution map of Crotalaria laburnifolia and C. larsenii in continental Southeast Asia.