Shorea assamica Dyer

Shorea species are trees, crown of mature trees dome shaped. Bark often fissured, light brown or reddish brown, bole straight, base of the trunk buttressed, flaked, branchlets glabrous or pubescent or lenticellate, white resin. Leaves simple, alternate, lanceolate-ovate to oblanceolate-elliptic, base obtuse to rounded, margins entire or repand, apex obtuse to acute, coriaceous, leathery, midrib impressed above and prominent beneath, lateral veins subparallel, curved near margins, tertiary veins scalariform, petiole stout, glabrous or sparsely pubescent, stipules large or small, persistent or caducous, coriaceous. Inflorescence axillary or terminal, lax panicles or cymes. Flowers bisexual, large, fragrant, pink or white, pedicel short, bracts persistent, caducous or ebracteate, calyx 5 lobed, tubular with short valvate lobes, imbricate, adnate to the receptacle, outer 3 larger than the inner 2 lobes, hairy, petals 5, white, pale yellow to pinkish strips, base slightly connate, sometimes free, pubescent outside. Stamens 15 or 25-100, adnate persistent, filaments somewhat flattened or tapering and filiform, anthers subglobose, narrow oblong-ovate, connective subulate, beyond anther lobes, hair-like. Ovary enclosed inside calyx tube, narrow ovoid, pubescent, tri-locular, 2 ovules per locule, stylopodium distinct or not, style subulate, stigma entire or tri-lobed. Fruit capsule or nutlike, indehiscent rarely dehiscent, enclosed in calyx tube with 3 outer accrescent larger and broader lobes and 2 inner ones like wings, calyx lobes base thick, saccate. Seeds 1, cotyledons large, fleshy.

Tree

Shorea species flowers are complete, bisexual, i.e., with functional male (androecium) and female (gynoecium), including stamens, carpels and ovary. Pollination is entomophilous i.e., by insects, or cleistogamy i.e., by self or allogamy i.e., by cross pollination. Flowering/Fruiting: August—October/November—March.

Seeds may be dispersed by autochory i.e., self dispersal, anemochory i.e., wind dispersal, zoochory i.e., dispersal by birds or animals, anthropochory i.e., dispersal by humans.

Large deciduous trees, up to 50 m tall, girth up to 7 m, crown of mature trees spreading or dome shaped. Bark fissured, exfoliating in big irregular flakes, reddish brown, bole straight, base of the trunk buttressed and wood pale brown, branchlets dark colored, yellow tomentose, lenticellate, with aromatic white resin. Leaves simple, alternate oblong-elliptic to broadly elliptic, about 6-18 x 3-7 cm across, base obtuse to cordate, margins entire, apex somewhat long mucronate or narrow abrupt acuminate tip, dark green, coriaceous, glabrous and shining above, sparsely softly pubescent beneath later becoming glabrous when mature, midrib slightly prominent above and prominent beneath, lateral veins 15-18 on either side of the midrib, subparallel, curved near margins, tertiary veins scalariform, petiole stout, sparsely pubescent, about 7-11 mm long, stipules lanceolate-falcate, fugacious, caducous, covered with silvery peltate scales, about 8 mm long. Inflorescence axillary or terminal, cymose panicles. Flowers bisexual, large, fragrant, white or cream white, about 1.3-1.5 cm across, pedicel subsessile, bracts minute, caducous, calyx 5 lobed, tubular with short valvate lobes, imbricate, adnate to the receptacle, grayish tomentose, outer 3 larger, elliptic, about 9 mm long, inner 2 lobes, about 6 mm long, petals 5, white, cream white, falcate-oblong, base slightly connate, apex acuminate, glabrous inside, velvety pubescent outside, 10-12 nerved longitudinally, about 1.3 cm long. Stamens 15 or more, adnate persistent, short, filaments somewhat flattened or tapering and filiform, anthers subglobose-ellipsoid, connective subulate, filiform. Ovary enclosed inside calyx tube, narrow ovoid, sparsely pubescent, tri-locular, 2 ovules per locule, stylopodium distinct or not, style subulate, filiform, minutely hairy near the base. Fruit capsule or nutlike, ovoid, apex acute, densely pubescent, about 1.2 x 2 cm across, enclosed in calyx tube with 3 outer accrescent larger lobes and broader lobes, linear obovate, about 6-12 x 0.8-2.5 cm long and 2 inner ones, smaller, spathulate, apex obtuse, about 8-12 veined, about 4-5 cm long, calyx lobes base thick, saccate, pubescent. Seeds 1, cotyledons large, fleshy.

Shorea species are susceptible to various insect pests, virus and fungi, affecting leaves, fruits and roots.

On slopes of evergreen forests, altitude 150-900 m.

Mixed deciduous, evergreen and semi-evergreen forests

Not evaluated (IUCN).

Wood used in plywood industry, boats, truck bodies and paper pulp.