Crotalaria tetragona Roxburgh ex Andrews (1812: 593)

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

41. Crotalaria tetragona Roxburgh ex Andrews (1812: 593) . Type:—Cultivated at Lord Valentia’s garden at Arley,

UK, from seeds sent from India by Roxburgh s.n. (BR Photo on webpage!).

= Crotalaria esquirolii Léveillé (1914: 299) . Type (lectotype designated here):— CHINA. 1 December 1904, Esquirol 260 (lectotype E00284744 !, isolectotypes E0028745!, E0028746 !).

Herb or shrublet, erect, 1–2 m high; young branches angular, brown pubescent. Leaves simple. Stipules narrowly linear, 2–5 mm long, persistent. Petioles 1.5–5 mm long, brown pubescent. Lamina lanceolate, 6–17 × 4–6.5 cm, base obtuse or rounded, apex acute or obtuse, margin entire, both surfaces puberulous; lateral veins 9–19 pairs. Inflorescences leaf-opposed, open racemes, 13–30 cm long; peduncle 4–4.5 cm long, brown pubescent. Bracts narrowly linear, 4–5 mm long, persistent. Pedicels 7–10 mm long, brown pubescent. Bracteoles inserted distally on the pedicel, narrowly linear, 3–4 mm long, persistent. Calyx 1.8–2.5 cm long, campanulate, bilabiate; tube 3–5 mm long; lobes triangular, 1.5–2 cm long, glabrous inside, brown pubescent outside. Corolla yellow. Standard: claw 3–4 mm long, white tomentose above, glabrous below, margin glabrous; blade broadly ovate, 2.5–2.7 × 1.8–2 cm, base obtuse or cuneate, apex acute, margin glabrous. Wings: claw 1.5–2 mm long, glabrous; blade oblong, 1.9–2 × 0.6–0.7 cm, base oblique, apex acute or obtuse, margin glabrous. Keel: claw 1.5–2 mm long, glabrous; blade ovate, 2.1–2.2 × 1.2–1.3 cm, beak spirally twisted, base oblique and white tomentose, apex attenuate, margin glabrous. Stamens: filaments fused for proximal 3–7 mm, free for distal 8–14 mm; anthers either narrowly linear, 3.5–3.8 mm long or oblong, 1.5–1.8 mm long. Ovary sessile, oblong, 0.8–1 mm long, brown pubescent; style 1.8–2 mm long, adaxially white pubescent in a single line along the distal edge, abaxially glabrous. Pods sessile, oblong 4–5 × 0.5–1 cm, brown, pubescent. Seeds reniform, 4–4.3 × 3–3.2 mm, black-brown.

Representative specimens: — CAMBODIA. Ratanakiri: Veal Thmor Lonqley , 22 November 2007, Cheng et al. CL273 ( P) . LAOS. No locality, 27 October 1920, Poilane 2189 ( L, P) . MYANMAR. Chin State: along walking trail between 17 miles from Mindat and Hilong Village , 9 December 2012, Fujikawa et al. 90676 ( QBG) . Magway: along roadside between Saw and Long Shei Village , 23 February 2014, Srisanga et al. 97201 ( QBG) . No locality, 8 July 1945, Jack & Millen 177 ( P) . THAILAND. Chiang Mai: Hod , 27 December 1978, Niyomdham et al. 157 ( AAU, BKF) . Kanchanaburi: Thong Pha Phum , 14 December 1993, Prinya & Santi 380 ( BK) . Loei: Dan Sai , 14 December 1966, Umpai 327 ( BK) . Mae Hong Son: Khun Yuam , no date, Chusie KY 262 ( QBG) . Nan: Doi Phu Kha National Park , 15 November 2001, Srisanga 2271 ( BKF, QBG) . Phitsanulok: Chattrakan , 20 November 2009, Norsaengsri 6336 ( QBG) . Phrae: at stream and wayside along road 1022 from Phrae to Ban Nam Klai , 15 November 1993, Larsen et al. 44399 ( AAU) . Suratthani: Wipawadee , 13 August 2013, Insorn 2 ( PSU) . Tak: Mae Sot , 13 January 1989, Paisooksantivatana y2310-89 ( BK) . Uttaradit: Phu Soi Dao , 19 November 2009, Norsaengsri 6321 ( QBG) . VIETNAM. Dak Lak: Ban Me Thuot , 30 November 1948, Schmid 768 ( P) . Phong Tho: Hoang Lien Son, 1 December 1937, Poilane 26737 ( BKF) . Gia Lai: 20 October 1978, Loc P 2299 ( HNU) . Kon Tum: Dak To , 20 October 1978, Loc & Ba P 2299 ( HNU) . Lai Chau: Phong Tho , 6 December 1937, Poilane 26737 ( P) .

Distribution: —Asia ( Myanmar, China, Thailand, Laos, Cambodia, Vietnam). ( Figure 25 ).

Ecology: —Open areas in pine forests and secondary forests dominated by bamboo, elevation 180–2070 m.

Notes: — Crotalaria tetragona resembles C. juncea but is instantly distinguishable by the 4-angled young branches, large leaves and persistent stipules. Crotalaria esquirolii was based on the syntypes Esquirol 260 (E!), Esquirol 340 (E!) and Esquirol 890 (E!). Esquirol 260 (E!) is chosen as lectotype because it is well preserved.

Figures

FIGURE 25. Distribution map of Crotalaria tetragona in continental Southeast Asia.