1. Chassalia curviflora (Wallich) Thwaites, Enum. Pl. Zeyl. 150. 1859.
弯管花 wan guan hua
Subshrubs, erect, 1-2 m tall; branches weakly flattened to subterete, glabrous or rarely sparsely puberulent. Leaves opposite; petiole 1-4 cm, glabrous; blade drying membranous to thinly papery and often yellowish green, oblong-elliptic, elliptic, oblanceolate, or narrowly lanceolate, 6-27 × 1.5-7.5 cm, glabrous, base cuneate to attenuate, apex acuminate to long acuminate; secondary veins 8-17 pairs, without domatia; stipules persistent, united shortly around stem, with interpetiolar portion broadly ovate or broadly triangular, 1.5-4.5 mm, acute or obtuse, entire or usually shortly bifid, with 1 or 2 bristles 0.3-1 mm, often gland-tipped. Inflorescence cymose, pyramidal to rounded, several to many flowered, puberulent; peduncle 1-5 cm; branched portion 3-7 cm; axes weakly flattened; bracts lanceolate to triangular or usually multifid, 0.5-3 mm. Flowers subsessile, trimorphic: with anthers exserted and stigmas included, with anthers included and stigmas exserted, or with anthers and stigmas both exserted. Calyx with hypanthium portion ellipsoid to obovoid, 1-1.5 mm, glabrous; limb 5-lobed, 0.5-1 mm; lobes 0.3-0.5 mm, acute. Corolla white with pink, red, or orange on lobes, outside glabrous to sparsely puberulent and longitudinally ridged to winged along tube then midribs of lobes; tube shallowly to markedly curved, straight or bent at base, 10-15 mm, pubescent inside; lobes (4 or)5, ovate-triangular, 2-2.5 mm, at apex thickened. Infructescence axes becoming swollen and red. Fruit purple, oblate to globose or weakly didymous, 5-7 × 6-9 mm. Fl. Apr-Jun, fr. Apr-Jan.
Wet places, forest understories, at low elevations; 100-2000 m. Guangdong, Guangxi, Hainan, Xizang, Yunnan [Bangladesh, Bhutan, Borneo, Cambodia, E and NE India (including Andaman Islands), Indonesia, Malaysia, Philippines, Singapore, Sri Lanka, Thailand, Vietnam].
At anthesis the corolla tube curves upward so that the base of the tube is suberect, the middle portion of the tube arcs toward the horizontal, and the mouth of the corolla opens outward to the side (Puff et al., Rubiaceae of Thailand, 101. 2005). Other authors have found this species distylous with the flowers 5-merous or infrequently 4-merous on aberrant individual flowers, as in many Rubiaceae; H. S. Lo (in FRPS 71(2): 61. 1999) described it as tristylous with often 4 corolla lobes.