1 | Cross section of stem with a central vascular cylinder and numerous peripheral vascular cylinders |
1' | Cross section of stem with a single vascular cylinder |
2 | Cross section of stem with 3 or 5 peripheral, equidistant vascular cylinders |
2' | Cross section of stem with 8 or 10 peripheral vascular cylinders, arranged in a circular way around the central cylinder |
3 | Stems trigonous, 5-ribbed, glabrous; cross section of stem with 3 (5) peripheral vascular cylinders; leaf rachis usually winged; leaflets with 2-4 rounded teeth just below the obtusely apiculate apex |
3' | Stems pentagonal, setulose-hispidulose; cross section of stem with 3 peripheral vascular cylinders; leaf rachis margined; leaflets entire or with 2-4 teeth widely spaced along the margins, or less often serrate, the apex acute or acuminate |
4 | Abaxial surface of leaflets strigose, canescent |
4' | Abaxial surface of leaflet glabrous, puberulent or ferruginous-pubescent, not canescent |
5 | Leaves 5-foliolate pinnate, abaxially glabrous; calyx glabrous or puberulent |
5' | Leaves biternate, abaxial surface sparsely ferruginous-pubescent; calyx tomentulose |
6 | Plant glabrous |
6' | Plant pubescent or puberulent |
7 | Leaflets with entire margins; samaras ≥ 3 cm long |
7' | Leaflets repando-dentate serrate; samaras 2-2.5 cm long |
8 | Plant glandular pubescent or puberulent; leaflets minutely puberulent with sparse, minute, glandular hairs along abaxial surface |
8' | Plant not glandular pubescent; leaflets sparsely pilose |