Dipterocarpaceae

Large forest trees with alternate, leathery leaves; flowers are small and unremarkable, but the fruit is unmistakable — a single nut fitted with two to five long wing-like sepal extensions that spiral it to the ground like a helicopter blade.

Dominant, often gigantic canopy trees of South and Southeast Asian rainforests, valued for both timber and resin — sal (Shorea robusta) is one of India's most economically and culturally important trees.

To check whether a plant belongs to Dipterocarpaceae, compare the leaf arrangement, leaf type, flower symmetry, fruit type, and one distinctive marker together. A single feature can mislead; the family pattern is the combination.