Description from Flora of China
Trees, to 12 m tall. Branchlets shortly gray-white woolly when young. Petiole 0.3-0.5 cm; leaf blade lanceolate or elliptic-lanceolate, 4.5-12.5 × 1.5-4.8 cm, thickly papery, abaxially densely yellowish brown stellate velutinous, adaxially glabrous or minutely sparsely puberulent, base obliquely rounded, apex long acuminate or caudate-acuminate. Flowers solitary, subterminal; pedicel ca. 0.5 cm; epicalyx lobes long-pointed, entire, ca. 6 mm. Sepals linear, 3.5-3.8 × ca. 0.25 cm, abaxially densely yellow-brown stellate tomentose, adaxially glabrous. Petals white, obovate, ca. 3 × 0.8 cm, glabrous, base tapering into narrow stalk, apex obtuse with acumen. Androgynophore ca. 8 mm, glabrous. Stamens slightly shorter than staminodes; staminodes ca. 1 cm, glabrous. Ovary ovoid, ca. 4 mm, densely yellowish brown tomentose. Capsule narrowly ellipsoid, ca. 8 cm, base tapering into 1-2 cm stipe, apex acute. Seeds ca. 3.5 cm including wing. Fl. Apr.
Pterospermum menglunense, though found within a protected area, is still treated as "Critically endangered" in the IUCN Red List because of the very small, fragmented population.
● Monsoon forests on limestone hills. S Yunnan (Xishuangbanna).