Thunbergia grandiflora

Thunbergia grandiflora Roxb., Bot. Reg. 6: 6. 1820; Sims, Bot. Mag. 50: t. 2366. 1822; Roxb., Fl. Ind. 2nd ed. 3: 34. 1832; Nees in Wall., Pl. Asiat. Rar. 3: 77. 1832; Wight, lcon. Pl. Ind. Orient. t. 872. 1844-1845; Bor & Raizada, Beaut. Ind. Climb. and Shrubs 108. 1954; Parker, For. Fl. Punj. ed. 1: 392. 1918 (Reprint 1973); ed. 3: 389. 1956; Malik & Ghafoor, Fl. Pak. @ eFloras.org p. 73; Fl. China @ eFloras.org 19: 377.

Large woody vine. Stem 4-angled, hollow, sulcate, pubescent. Leaves opposite, simple; petiole 1-7 cm long, scaberulous, grooved; leaf blade ovate to triangular-ovate, 5-14 cm x 4-14 cm, leathery, both surfaces pubescent, palmately 3-7-veined, base cordate or subcordate, margin undulate, irregularly angular on basal half or irregularly dentate, minutely spinescent, rarely entire, apex acuminate to acute. Flowers solitary or paired in leaf axils or arranged in axillary or terminal drooping racemes with 2-4 flowers per node; peduncle 4-12 cm long, scaberulous, sulcate, pubescent; bracts subulate to linear-subulate, 2-6 mm x 1-1.5 mm; bracteoles 2, free or connate, 2.5-4 cm x 1.5-2.5 cm, both surfaces pubescent, 5-7-veined, base truncate, margin entire or ciliate, apex acute with a short mucro or acuminate. Flowers bisexual, subactinomorphic, hypogynous, blue or purple with white centre, 6-8 cm long and ca. 8 cm across, pedicellate, trumpet-shaped. Calyx ca. 2 mm long, cupulate, unlobed, truncate, densely pubescent, velvety-rimmed, purplish. Corolla bluish or purple with a whitish throat, 6-8 cm long and ca. 8 cm across, outside glabrous; tube 3-4.5 cm long, basally cylindric and ca.10 mm wide for about 2 cm, then gradually widened to ca. 5 cm at throat; limb subactinomorphic, lobes 5, +/- equal, ovate, ca. 3-3.5 cm x 3-3.5 cm. Stamens 4, didynamous, all fertile, inserted at the throat; filaments ca. 1.5 cm long, base flattened; anthers 1 cm long, oblong, bithecous, thecae parallel, bearded, anterior anthers with a single spur, posterior ones with 2 sharply curved spurs or appendages. Carpels 2, syncarpous; ovary 4 mm x 4 mm, 2-locular, each loculus with 2 collateral ovules, glabrous; style ca. 2 cm long; stigma with 2 unequal lobes.

Capsule 1.2-1.5 cm long, pubescent, basal part 1.3-1.8 cm in diameter, beak 2-2.5 cm long, flat. Seeds ovate in outline, compressed, verrucose. (Fruits not observed)

Flowering and Fruiting: July to December
Common Names: : Bengal Clock Vine, Bengal Trumpet Clock Vine, Blue Sky Flower, Trumpet Vine