Caesalpinia hymenocarpa

Author: (Prain) Hattink

Morphological description (hymenocarpa Caesalp pod/lf FT20)
Liana or shrub ; branchlets armed with recurved prickles. Stipules scale-like, c. 0.5 by 0.5–1 mm, appressed.

Leaves: rachis 20–40 cm, shortly hairy; pinnae 6–10 pairs, 4–10 cm long, hairy, unarmed. Leaflets opposite or alternate, 10–18 per pinna, petiolulate (c. 1 mm), membranous, obovate or obovate-oblong, 11–28 by 5–16 mm, base subequal to unequal, apex rounded to retuse, margins parallel or curved, surfaces pubescent or glabrous.

Inflorescences axillary and terminal, paniculate, 30–50 cm long, the rachis pubescent; pedicels 8–15 mm, articulated 1–4 mm below the top.

Flower buds pubescent. Hypanthium c. 1 mm deep and 6 mm wide. Sepals: lowest one deeply cucullate, 6–10 by 3.5–5 mm, ciliate. Petals: standard with claw 3–4 mm long, prolonged into a ligule (c. l mm long) with a bilobed or erose apex, margins hairy, limb reniform to orbicular, 3–4 by 4–6 mm, reflexed; other petals with claw c. 0.5 by 1 mm, hairy or glabrous, the limb suborbicular to reniform, 7–10 by 10–11 mm. Stamens exserted; ¾laments 7–17 mm; anthers 2.5 mm long, glabrous. Pistil glabrous; ovary 5 by 1 mm, 4–6-ovuled; style c. 12 mm, stigma 1 mm in diameter, shortly ciliate.

Pods (up to 0.5 cm stiped) thin, indehiscent, 6–15 by 2–3(–4) cm (incl. the 0.6–0.8 mm wide longitudinal wing), base cuneate, apex sometimes rounded, normally hooked, dull to shining, weakly reticulate, (1–)3–6-seeded (hymenocarpa Caesalp pod/lf FT20 ;hymenocarpa Caes pod Reinw9/4 ).

Seeds ellipsoid in outline, flat, 5–10 by 3–5 by 1 mm, dull.

Sri Lanka, India, Burma, Laos, Cambodia, China, Thailand; in Malesia: Andaman Islands, Java (Jakarta), Lesser Sunda Islands (Sumbawa, Flores, Alor, Timor, Tanimbar).

Habitat & Ecology
Hill jungle, monsoon forest, riverbanks, up to 850 m altitude.