Caesalpinia sumatrana

Author: Roxburgh

Morphological description
Liana to 20 m, glabrous in all parts except sometimes hairy on the leaflets; branchlets unarmed or sparsely armed with up to 5 mm long prickles (sumatrana Caes bark Tan 2a ). Stipules none or early caducous.

Leaves: bipinnate; rachis 30–50 cm; pinnae 4–8 pairs, unarmed or sparsely armed with recurved prickles. Leaflets alternate, except at the top often an opposite pair, 7–12 per pinna, petiolulate (2–3 mm), oblong, 2.5–7 by 1.5–5.5 cm, base cuneate or truncate, apex retuse or rounded, rarely obtuse, glabrous, sometimes hairy beneath.

Inflorescences supra-axillary and terminal, paniculate, 30–80(–100) cm long; bracts boat-shaped, c. 1 by 0.5 mm; pedicels 5–20 mm, articulated at the base.

Flower buds oblong, glabrous. Hypanthium 3–7 mm deep and 4–8 mm wide. Calyx-tube red, 6–15 by 4–8 mm, at length circumscissile above the hypanthium and falling off with the corolla and stamens; calyx lobes half-orbicular, 2–10 mm long, often ciliate. Petals pink, more or less equal, spathulate, 12–32 by 8–12 mm, clawed (claw 10–15 mm). Stamens pale pink with brown anthers, not or slightly exceeding the petals; the filaments 15–29 mm; anthers c. 1.5–3 mm long, glabrous. Pistil 12–30 mm long, glabrous; ovary 6–15 mm long, 2–4(–8)-ovuled; style 6–15 mm; stigma as wide as the style, ciliate.

Pods dark wine-red, subsessile, oblong, 10–17 by 3–6 cm (incl. the 1–2 cm wide wing), cuneate at the base (sumatrana Caes podbase Reinw9/4 ), rounded or hooked at the apex, smooth or slightly reticulate-nerved, 1–8-seeded.

Seeds brown, flat, elliptic, c. 11 by 7 mm.

India?, Solomon Islands (Guadalcanal); in Malesia: Sumatra (West-coast, Bengkulu), Malay Peninsula (most of the provinces), Borneo (Sabah), Java (W & E parts), New Guinea (Irian Jaya: Jayapura; Papua New Guinea: W Sepik, Morobe, Central Prov., Papuan Is., New Britain, New Ireland).

Habitat & Ecology
Lowland rain forest and secondary forest, forest fringes, along roads, usually at low altitudes, sometimes up to 1000 m.