Plant of the month May,2022
Eng (thai)

 

 

Polygala arillata Buch.-Ham. ex D.Don, Prod. Fl. Nep.: 199. 1825.
Polygalaceae

Description: Shrub 1–5 m. Leaves alternate, elliptic, oblong, ovate or obovate, 5–13 (18) × 1.5–8.5 cm, sparsely hairy on veins; apex acuminate; base cuneate to rounded; petiole 0.5–1 cm. Inflorescence unbranched, rather slender, erect to pendulous with 10–60 flowers, rather lax, shortly hairy, to 20 cm; bracts 3, caducous, ovate-caudate, to 2.8 mm. Flowers yellow; pedicel ca 5 mm long. Sepals 5; outer sepals ciliate, the lower two oblong to ovate, 3.5–4.5 mm long, the upper saccate at the base, 6–8 mm long; alae obovate, cucullate, 1–1.4 cm long, minutely ciliate. Petals 3, uneaqual; upper petals 1–1.4 cm long, free parts oblong, 5–6 mm long; keel 1.2–1.6 cm long, boat-shaped in the apical part, enclosing the anthers and stigma, appendage finely divided with more or less connate lobes. Stamens 8, connate in a staminal sheath, 1-1.4 cm long. Disk annular. Ovary 2-locular, winged, ca 2 mm; style elongate, ca 1 cm long; stigma 2-lobed. Capsule green or pale purple, more or less two lobed, glabrous, with prominent concentric ridges, ca 1 × 1–1.5 cm, wing ribbed, up to 4 mm wide. Seeds 2, spheroid, glabrous, ca 5 mm; aril bright orange, apically projecting and covering up to half the seed, 2–5 mm long.

 

 

Distribution: S Asia, S China, Indochina and N, NE, E & SE Thailand, montane forest, 900–2,300 m.

Thai name: ต่างไก่ป่า (tang kai pa)

Photos: Sukontip Sirimongkon (Khao Yai) / Rachun Pooma (Doi Inthanon)

References: 
Pendry, C.A. (2001). Polygalaceae. In Flora of Thailand Vol. 7(3): 501–502.