1	Grows on limestone mountain; leaflets (3) 5 (7); nuts compressed-globose; husk smooth without longitudinal ridges, sparely orange-glandular; lacunae present in nutshell	2
–	Grows on mountain slopes, valleys and riverbanks; leaflets 5–7 (9); nuts obovoid, ellipsoid or subglobose; husk wrinkled with longitudinal ridges; densely orange-glandular; lacunae absent in nutshell	3
2	Leaflets mostly broad obovate, papery, rough, margin serrate	C.poilanei
–	Leaflets elliptic to elliptic-lanceolate, more or less leathery, glossy, margin obtusely serrate	C.kweichowensis
3	Petiole tomentose; husk slightly winged	C.tonkinensis
–	Petiole glabrescent; husk conspicuously winged	4
4	Husk winged to middle	C.hunanensis
–	Husk winged to base	C.cathayensis