This evergreen oak possesses leathery leaves with a dense, felt-like indumentum on the undersurface.    From Wordnik.com.  [Hengduan Mountains subalpine conifer forests] Reference

The differentiating qualities relate to the shape and indumentum of the leaves.    From Wordnik.com.  [Species and Varieties, Their Origin by Mutation] Reference

Zonam eiiim iiitelligit, no autem indumentum.    From Wordnik.com.  [Suidae Lexicon, Græce & Latine] Reference