1	Leaves deciduous		(2)
+	Leaves evergreen		(6)
2 (1)	Young branches and twigs with 4 corky wings.		30 E. alatus
+	Young branches and twigs without wings		(3)
3 (2)	Leaf blade broadly linear or oblong-lanceolate, 4-7 × as long as wide.		34 E. euscaphis
+	Leaf blade ovate to elliptic, less than 4 × as long as wide		(4)
4 (3)	Leaf blade obovate or elliptic-obovate.		31 E. centidens
+	Leaf blade ovate to ovate-elliptic		(5)
5 (4)	Leaf blade margin finely and sharply serrulate; flowers from greenish pink to red; style long and persistent.		39 E. verrucosoides
+	Leaf blade margin crenulate; flowers light yellow or greenish yellow; style short and invisible.		33 E. distichus
6 (1)	Flowers 4- or 5-merous; cymes with many flowers; leaf blade margin ciliate.		37 E. lucidus
+	Flowers 4-merous only; cymes with less than 7 flowers; leaf blade margin without cilia		(7)
7 (6)	Leaf blade entire.		36 E. hukuangensis
+	Leaf blade margin crenulate to serrate		(8)
8 (7)	Leaf blade small, 4-7 cm.		38 E. tashiroi
+	Leaf blade large, 9-15 cm		(9)
9 (8)	Leaf blade mainly obovate, margin often serrulate to ciliate; capsule lobes often bending backward.		32 E. dielsianus
+	Leaf blade mainly elliptic, margin entire or obscurely crenulate; capsule lobes never bending backward.		35 E. hainanensis