1. Prismatomeris tetrandra (Roxburgh) K. Schumann in Engler & Prantl, Nat. Pflanzenfam. 4(4): 138. 1891.
四蕊三角瓣花 si rui san jiao ban hua
Coffea tetrandra Roxburgh, Fl. Ind. 2: 193. 1824; Octotropis terminalis C. B. Clarke; Prismatomeris connata Y. Z. Ruan; P. connata subsp. hainanensis Y. Z. Ruan; P. multiflora Ridley; P. tetrandra subsp. multiflora (Ridley) Y. Z. Ruan.
Shrubs or small trees, to 8 m tall; branches quadrangular to subterete, glabrous. Petiole 4-15 mm, glabrous; leaf blade drying leathery to stiffly papery and rather shiny, lanceolate, elliptic, elliptic-oblong, ovate, obovate, or oblong-lanceolate, 4-18 × 2-6 cm, glabrous, base cuneate to acute, apex acuminate or acute to obtuse; secondary veins 5-9 pairs; stipules with sheath portion 0.2-1 mm, truncate, persistent or deciduous by fragmentation, bilobed, lobes linear to narrowly triangular, 0.1-0.5 mm, caducous. Peduncles 1-16 and fascicled or umbellate, 5-35 mm, simple or bearing an umbellate group of pedicels, at base with stipuliform bracts; pedicels when present 5-15 mm. Flowers pedunculate or pedicellate. Calyx glabrous or sparsely glandular-puberulent; hypanthium portion hemispherical, 1.5-2 mm; limb 1-2 mm, truncate or 4- or 5-denticulate. Corolla white or pale purple, salverform, glabrous outside; tube 14-20 mm; lobes 4 or 5, lanceolate, 7-10 mm, abaxially (i.e., dorsally) ridged at least in bud, acute to obtuse. Drupes subglobose, 8-12 mm in diam., glabrous, smooth. Fl. May-Sep, fr. Sep-Dec.
Forests, thickets; 300-2400 m. Fujian, Guangdong, Guangxi, Hainan, S Yunnan [Cambodia, India, Thailand, Vietnam].
Johansson (Opera Bot. 94: 29. 1987) recognized two subspecies, Prismatomeris tetrandra subsp. tetrandra and P. tetrandra subsp. malayana (Ridley) J. T. Johannson; he reported only subsp. tetrandra from China. However, Puff et al. (Rubiaceae of Thailand, 118. 2005) noted that further observation shows that even these taxa cannot be completely separated either morphologically or geographically. Y. Z. Ruan (in FRPS 71(2): 178. 1999) included the Chinese plants in P. tetrandra subsp. multiflora, which Johansson synonymized with subsp. tetrandra. Ruan (loc. cit.) reported that the flowers of P. connata are occasionally unisexual; this was not further documented there and has not been reported by others nor confirmed with specimens. Ruan (loc. cit.: 179) also described the calyx lobes as ca. 3 mm, which has not been reported by other authors nor seen on the rather ample materials studied.
This species was newly reported from India by Ayappan and Parthasarathy (J. Econ. Taxon. Bot. 29: 802-804. 2005), and its distribution in Cambodia and Vietnam is here reported based on specimens at P annotated by Johansson after the publication of his article.