Rubia cordifolia L.

Scrambling, climbing or creeping plant, less often tussock-forming, with branched stems 0.3–6 m. long; stems brittle, with quite strong curved prickles on the 4 ribs and either pubescent all over or at least with hairs beneath the nodes; roots usually quite woody, containing a red dye.. Leaves in whorls of 4(–8) or sometimes paired; blades lanceolate to broadly ovate, 0.7–8.5 cm. long, 0.2–4.2 cm. wide, acuminate at the apex, rounded to cordate at the base, scabrid pubescent above, glabrescent to often densely covered with long white hairs beneath at least when young, margins often with curved prickles, 5–7-nerved from the base, the nerves sometimes with scattered curved prickles beneath; petioles 0.8–1.5 cm. long, with recurved prickles and often pubescent as well.. Inflorescences usually numerous, scattered along the stem, fairly lax to rather dense, 0.5–2.5 cm. long; peduncles 1–2.5 cm. long; pedicels 0.2–6 mm. long; bracts elliptic, 1.2–1.5 mm. long, 0.3–0.4 mm. wide.. Flowers glabrous.. Calyx-tube (0.25–)0.5–0.8 mm. long and 0.8–1.4 mm. wide.. Corolla yellowish, green, greenish cream or greenish yellow, often pink-or purple-tipped in bud, 4–6 mm. wide; tube 0.2–0.8 mm. long; lobes usually triangular, 1.5–3 mm. long, 0.6–1.3 mm. wide, apiculate, margins minutely papillate.. Fruit glabrous, brownish black; lobes globose, 2.5–5 mm. in diameter; pyrenes globose, 3 mm. in diameter.. Seeds globose, 1.2–2.9 mm. in diameter.

It is a tropical plant. It can grow in a wide range of conditions. It grows from sea level to 2,600 m altitude. In Tanzania it grows between 1,100-2,600 m above sea level. In Indonesia it grows from 500 m above sea level to high in the mountains. In Sichuan and Yunnan.

The young leaves are eaten as a side dish. They are usually steamed. They are also burnt and used as a vegetable salt. The ash is soaked in water and filtered and this is used to soften other vegetables when cooking. It can be used as a substitute for sodium bicarbonate. The fresh fruit are eaten. The root is dried as a powder and used as flavouring in local liquor.

It can be grown by seed or cuttings. Fresh seed grows most quickly. Plants should be grown in light shade.