e-Flora of Thailand
Volume 4 > Part 3 > Year 2018 > Page 230 > Leguminosae-Papilionoideae > Ormosia
6. Ormosia mekongensis Mattapha, Suddee & Rueangr.wfo-0001444022
Thai Forest Bull., Bot. 45(2): 119, f. 1–2. 2017. Fig. 56. Plate IX: 1–2.
Accepted Name : This is currently accepted.
Description : Tree to 15 m tall, young shoots, leaf-rachis, inflorescences and calyces, with short hairs. Stipules absent. Leaves with petioles 2–4 cm long; rachis 4–8 cm long, densely hairy; topmost (ultrajugal) part of leaf rachis up to 2 cm long. Leaflets 5–7, elliptic, 5–6 by 1.5–2 cm, apex acuminate, base cuneate, coriaceous, margin entire, upper surface glabrous, lower surface hairy with scattered adpressed hairs, glaucous; lateral veins 6–8 pairs; petiolules ca 5 mm long. Inflorescences mostly terminal, paniculate, sometimes axillary, racemose, 8–10 cm long, densely hairy; pedicels 5–6 mm long, densely hairy. Calyx campanulate, 2.5–3 mm long, persistent, becoming woody in fruit; lobes triangular, 4–5 by 3.5–4 mm, longer than the tube, apex acute, both sides densely hairy, upper lobes 2, lower lobes 3. Corolla light yellowish or light pinkish, slightly fragrant; standard orbicular with a green patch at the base on the ventral side, 10–12 by 9–10 mm, apex emarginate, base tapering to claw, margin entire, both sides glabrous, claw ca 3 mm long; wings oblong, 9–10 by ca 4 mm, apex obtuse, base slightly auriculate, both sides glabrous with a green patch at base on the inner side, claw ca 3 mm long; keels oblong-elliptic, 8–9 by ca 4 mm, apex acute, based slightly auriculate, outside hairy along median vein, inside glabrous, claw ca 5 mm long. Stamens all free; filaments flattened, 10–12 mm long, glabrous; anthers ca 1 by 0.5 mm, glabrous. Ovarydensely adpressed hairy; ovules 1–3; style 8–9 mm long, glabrous. Pods flattened, discoid, convex at centre, 2.2–2.4 by 2.8–3.3 cm, woody, brown to grey when dry, hairy, dehiscent, slightly septate, margin crested. Seeds 1 (–2), orbicular to ellipsoid, 0.8–2 by 1–1.5 mm; testa bright red.
Thailand : NORTH-EASTERN: Sakon Nakhon (Phu Phan NP – type: Mattapha et al. 1164 -BK BKF [2 sheets] E K KKU L P QBG); EASTERN: Ubon Ratchathani (Khong Chiam, Dong Na Tham Forest, Pha Tam NP).
Distribution : Endemic.
Ecology : Dry deciduous to dry evergreen forests, 320–500 m alt.
Vernacular : Ma klam mae khong (มะกล่ำแม่โขง).