丝梗茜草 si geng qian cao

Vines, herbaceous, to 2-3 m tall; stems quadrangular or narrowly 4-winged, glabrous or subglabrous, retrorsely aculeolate on angles. Leaves opposite; petiole (2-)3-15(-25) mm; blade drying thinly leathery or papery, ovate or rarely ovate-lanceolate, 2-9 × 1-4.5 cm, both surfaces glabrous and smooth or sparsely aculeolate along veins, base rounded, subcordate, or obtuse, margins entire and smooth, apex acute to acuminate; principal veins 3 or 5(or 7), palmate, adaxially impressed; stipules ovate, ca. 5 mm, usually caducous. Inflorescences thyrsoid, paniculiform, with terminal and axillary, many-flowered cymes and slender, subfiliform, smooth and glabrous axes. Flowers unknown. Fruiting pedicels 7-14 mm; mericarp berries black, 4-5 mm in diam. Fr. in late winter.

● Forests; 1000-1500 m. Yunnan (Malipo).

We have seen no authentic specimens of Rubia filiformis, but there is a good drawing in H. S. Lo (in FRPS 71(2): 297, t. 64, f. 1-5. 1999). The species evidently belongs to the R. siamensis group of R. sect. Oligoneura.