1	Capsule with tubercles (not prickles), entire surface densely tuberculate.		28 E. verrucocarpus
+	Capsule with prickles, not tubercles		(2)
2 (1)	Capsule with needle to threadlike prickles, sparsely covering surface		(3)
+	Capsule with sturdy prickles, densely covering surface		(7)
3 (2)	Prickles fine and slender or sometimes needlelike; capsule large, 1.3-1.8 cm in diam..		25 E. lushanensis
+	Prickles straight, not fine and slender; capsule small, less than 1 cm in diam		(4)
4 (3)	Leaf blade entire.		26 E. potingensis
+	Leaf blade crenulate to serrate		(5)
5 (4)	Dwarf shrubs, under 30 cm tall.		19 E. aculeolus
+	Shrubs, more than 1 m tall		(6)
6 (5)	Leaf blade 5-12 × 3-4.5 cm, veins impressed adaxially, prominent abaxially; capsule ca. 8 mm in diam..		23 E. chui
+	Leaf blade 4-6 × 2-3 cm, veins invisible; capsule 8-10 mm in diam..		27 E. spraguei
7 (2)	Capsule grayish green or gray when dry, prickles more than 1 cm, flattened at base.		17 E. actinocarpus
+	Capsule brown, yellow, tawny, black, or purple when dry, prickles less than 1 cm		(8)
8 (7)	Inflorescences more than 10 cm; flowers more than 10		(9)
+	Inflorescences less than 9 cm; flowers less than 9		(10)
9 (8)	Leaf blade ovate or ovate-elliptic, adaxially wrinkled, petiole 5-8 mm.		20 E. balansae
+	Leaf blade oblong to elliptic, adaxially never wrinkled, petiole 1-2 cm.		16 E. acanthocarpus
10 (8)	Leaf blade pubescent on both sides.		21 E. acanthoxanthus
+	Leaf blade glabrous		(11)
11 (10)	Leaves sessile or petiole less than 4 mm		(12)
+	Leaf petiole more than 8 mm		(13)
12 (11)	Leaf blade less than 4 × 2 cm.		22 E. chenmoui
+	Leaf blade ca. 5 × 2-3 cm.		24 E. echinatus
13 (11)	Leaf blade leathery, 7-10 × 3-6 cm; capsule 1-1.5 cm in diam..		18 E. aculeatus
+	Leaf blade thinly leathery or papery, 10-15 × 2.5-4.5 cm; capsule 1.5-2 cm in diam..		29 E. wilsonii