1Flowers always borne on bare older branches, and organized in a condensed cluster on short leafless lateral shoots; perianth cup-shaped, 5-7-lobed; ovary (fruit) stipitate. Fruit a dry, flat, winged samara. Embryo straight.
1'Flowers axillary, or rarely borne in a condensed capitate thyrse on older branches (Gironniera celtidifolia); perianth 4-5-lobed, with the lobes free from one another except for their base; ovary sessile. Fruit a fleshy drupe. Embryo variously curved.
2Leaves triplinerved at base, or if pinnately nerved the stipules do not leave a circular scar around the node; lateral nerves less than 5 pairs.
2'Leaves pinnately nerved; lateral nerves more than 5 pairs; stipules free but overlapping each other, in falling leaving circular scar around the node
3Stipules intrapetiolar, connate
3'Stipules extrapetiolar, free.
4Female flowers borne in condensed, multiflowered raceme. Perianth of male flower induplicate-valvate. Fruit compressed, elliptic lens-shaped in cross-section
4'Female flowers solitary in the axils of leaves or borne in a cymoid cluster of 2-3. Perianth lobes of male flowers imbricate. Fruit faintly 3-5-angular in cross-section.
5Male flowers borne in a 2-3-flowered cymoid inflorescence or in a much-branched paniculate, subterminal inflorescence. Female flowers borne in a racemose cluster of 2-10 or in a ♂♀, much-branched racemose inflorescence; staminodes mostly present. Cotyledons broad, variously folded or curved
5'Male flowers organized in a condensed, multiflowered raceme. Female flowers always solitary or rarely borne in a 2-3-flowered racemose, ♂♀ inflorescence; staminodes always absent. Cotyledons narrow, incurved