云南翅子树 yun nan chi zi shu

Small trees, to 5 m tall. Branchlets gray puberulent when young. Leaf blades dimorphic: those of young trees and coppiced branches with petiole up to 24 cm, blade palmately 5-divided, lobes nearly linear, ca. 16 × 11 cm, base peltate, apex acuminate; those of mature trees with petiole 1-1.5 cm, blade oblong-obovate in outline, usually irregularly lobed, 6.5-8.5 cm, leathery, abaxially densely yellowish brown stellate puberulent, adaxially glabrous, base cordate or obliquely cordate, apex truncate with obtuse acumen; lateral veins 5-6 per side of midrib. Flowers unknown. Capsule ovoid-ellipsoid, obscurely 5-angular and with 5 nearly flat foveolate spots, ca. 4 cm, densely brown puberulent, base narrowed into ca. 6 mm stipe, apex obtuse. Seeds ca. 2.8 cm including wing, wing brown, apex obtuse.

● Forests on limestone cliffs and summit ridges; 1400-1600 m. S Yunnan.

Pterospermum yunnanense is classified as "Critically endangered" in the IUCN Red List because there are few mature individuals and regeneration is poor.