Author: (Bentham) Prain
Morphological description
Tree up to 40 m high and c. 70 cm in diameter (echinc Sindora stem JRN6-8). Stipules foliaceous, subintrapetiolar, falcate, up to c. 8 mm long, acuminate, rounded auriculate at base, reticulate and finely puberulous on both surfaces, early caducous.
Leaves paripinnate, 3- or 4-jugate (echonicalyx Sindora TYPE detail ); petiole 2-2.5 cm and rachis c. 7 cm long, minutely puberulous, glabrescent; petiolules very short or subsessile, up to c. 2.5 mm, pubescent, glabrescent. Leaflets coriaceous, elliptic or elliptic-oblong, rarely obovate, 4-7.5 by 2-3 cm, lower ones usually smaller than the upper ones; apex obtuse, the very tip slightly notched; base obtuse or rotund, often symmetric; upper surface glabrous; lower surface puberulous especially on the midrib.
Inflorescences paniculate, up to 15 cm long, lateral branches up to c. 7 cm long, both rachis and branches densely puberulous; bracts and bracteoles triangular, ovate, or lanceolate, 4-7 mm long, puberulous on both surfaces; pedicels subsessile or very short, up to 3 mm, puberulous.
Flower: Calyx lobes 4, broadly ovate, or lanceolate, 4-5.5 by 1.5-2.5 mm, puberulous outside and bearing some spiny outgrowths outside (echonicalyx Sindora TYPE detail ), puberulous inside. Petal 1, slightly obovate or elliptic, c. 5 by 2.5 mm; puberulous outside and glabrous inside. Stamens: 10 (9+1), united basal parts of the filaments very short; free filaments up to c. 10 mm, slightly hairy at the lower part; fertile anthers various in size, the larger ones ovoid-ellipsoid, c. 2.5 mm long, the others smaller. Ovary sessile, subrhomboid, c. 5 mm long, densely hairy, with numerous minute, spiny outergrowths, 2-4-ovuled; style up to c. 10 mm, recurvate, glabrous or sparsely hairy in the basal part; stigma small, capitate.
Pods (echinoc Sindora tr/pod JRN6-6; echinoc Sindora pod JRN6-10) on a very short peduncle, ovoid or broadly ellipsoid, or suborbiculate, 4-6.5 by 3.5-6 cm, flattened, covered with close, hard, straight spines (up to c. 4 mm); beak curvate, c. 8 mm long; 1- or 2(or 3)-seeded.
Seeds arillate.
Distribution
Thailand (Peninsula); Malesia: Riau Archipelago, Malay Peninsula (common, throughout), Borneo (Sabah).
Habitat
In forests on hillsides and ridges, from lowland up to c. 600 m.
Notes
1. There is one sterile sapling collection, FRI 1202 (L), c. 6 m tall, bearing prominent foliaceous stipules (up to 18 by 8 mm), and rather larger leaflets (up to 15 by 7 cm) with acute or shortly acuminate apex and prominently reticulate venation on both surfaces.
2. Sindora echinocalyx is very closely allied to Sindora wallichii but can be distinguished from the latter even in sterile material by the leaflets with prominently reticulate venation on the upper surface (against smooth, shining and not reticulate).