Tree, wood vessels mostly solitary. Leaves simple, spread (on lateral branches), penninervous, entire, margin and leaf tip glandular; upper epidermis often double and provided with mucilaginous cells; midrib sulcate above. Stipules caducous. Indumentum of simple hairs. Flowers actinomorphic, bisexual, in axillary and terminal panicles; bracts with glandular margin. Sepals 5, free, nerved as the petals are, unequal, imbricate. Petals 5, free, very unequal, imbricate; posterior saccate with reflexed emarginate limb, lateral spathulate, spreading, anterior oblique, keel-like together, including at their base the genitals; entrance of the sac with one fleshy hairy concave gland (easily breaking into 2 parts). Stamens 6 monadelphous, tube split posteriorly, eventually with some loose minute teeth, minute upper part of filaments free; anthers oval, slightly emarginate at the base, 2-celled, opening with one slit, gaping; exine (judging from boiled flowers) reticulate. Ovary hairy, easily falling into 3 parts as does the simple style; stigma small punctiform. Ovule pendulous solitary. Fruit composed of 3 easily detaching samaras. Seeds (n.v.) elongate, shortly hairy, exalbuminous; radicle very short.