Description from Flora of China
Lagerstroemia collettii Craib; L. corniculata Gagnepain.
Trees, to 8[-17] m tall. Branchlets terete, densely gray puberulous. Petiole 3-6 mm; leaf blade oblong or oblong-elliptic, 10-14 × 3-5.5 cm, gray puberulous, glabrescent, lateral veins [5-]8 or 9 pairs, base usually oblique, apex obtuse. Panicles 11-27(-45) cm, densely gray puberulous, open, sparsely flowered. Floral tube 6(or 7)-merous, 5-9 mm, gray puberulous, 6- or 7-ribbed or ribs rounded, obscure; sepals ca. 3 mm, adaxially glabrous; annulus absent; epicalyx segments deltate, ca. as long as sepals, abaxially keeled, slightly incurved in bud. Petals pink-purple, oblong, 7-9 mm including claw 2-3 mm. Stamens numerous, dimorphic. Ovary glabrous. Capsules ovoid, ca. 1.3 × 1.2-2 cm, 5-valved, finely wrinkled at maturity. Seeds including wing ca. 1.8 cm. Fl. Oct, fr. Dec-Nov.
Rain forests, rain forest margins. S Yunnan [Cambodia, Laos, Myanmar, Thailand, Vietnam].