1	Leaves 2- or 3-pinnate; leaflets dichotomously forked.		(2)
+	Leaves 1-pinnate; leaflets simple.		(4)
2 (1)	Leaves 2-pinnate; leaflets dichotomously 1(-3)-forked into linear, often irregular segments (ultimate leaflets), each 10-38 cm with apex attenuate to long acuminate		3 Cycas micholitzii
+	Leaves 3-pinnate; secondary leaflets dichotomously (2 or)3-5-forked into linear, regular segments.		(3)
3 (2)	Leaves 1(or 2), to 7 m; segments obovate-linear, apex shortly acuminate to caudate; sterile blade of megasporophylls with 25-35 subulate lobes		1 Cycas multipinnata
+	Leaves (3-)5-11(-15), to 2.7 m; segments linear, apex long attenuate or long acuminate; sterile blade of megasporophylls with 39-51 filiform lobes		2 Cycas debaoensis
4 (1)	Leaves strongly V-shaped in cross section, longitudinally recurved; margin of leaflets revolute (slightly recurved in C. taitungensis).		(5)
+	Leaves flat to inconspicuously V-shaped in cross section, longitudinally flat; margin of leaflets not revolute (except in C. ferruginea).		(7)
5 (4)	Trunk not tomentose at apex; bark pale gray, smooth toward base of trunk; mature leaflets glaucous		15 Cycas hongheensis
+	Trunk densely tomentose at apex; bark black, scaly; mature leaflets not glaucous.		(6)
6 (5)	Leaflets strongly recurved along margin; sterile blade of megasporophylls ovate to narrowly so, deeply laciniate; sclerotesta of seed not grooved on sides		6 Cycas revoluta
+	Leaflets flat or slightly recurved along margin; sterile blade of megasporophyll suborbicular or rhombic-orbicular, pectinate; sclerotesta of seed with 2 or 3 irregular grooves on each side		7 Cycas taitungensis
7 (4)	Trunk subterranean, base not swollen; median leaflets (12-)18-25 mm wide, margin often undulate; median microsporophylls blunt.		(8)
+	Trunk not subterranean (or, if so, then base swollen); median leaflets 6-11(-14) mm wide, margin flat (revolute in C. ferruginea); median microsporophylls spinose.		(9)
8 (7)	Petioles green in 1st year; megasporophylls 5-15(-20), loosely grouped, sterile blade divided into 15-25 lobes		4 Cycas balansae
+	Petioles blue in 1st year, later green; megasporophylls 25-50, densely grouped, divided into 33-45 lobes		5 Cycas segmentifida
9 (7)	Leaves (0.7-)1-3 m × 30-60 cm; terminal lobe of sterile blade of megasporophyll usually flattened.		(10)
+	Leaves 0.5-1(-1.3) m × (12-)20-30(-40) cm; terminal lobe of sterile blade of megasporophyll subulate, not flattened.		(12)
10 (9)	Trunk inflated; bark white-gray, nearly smooth toward base of trunk; median leaflets often less than 10 mm wide; petiole densely spinose from base upward; seeds 3.5-4.5 cm		9 Cycas hainanensis
+	Trunk cylindric; bark dark, scaly; median leaflets often more than 11 mm wide; petiole without spines or with sparse spines near base; seeds 2.5-3 cm.		(11)
11 (10)	Leaflets longitudinally inserted at 55-75° to rachis; apex of cataphylls with hard point; sterile blade of megasporophyll rhombic-ovate; sclerotesta of seed finely verrucose		10 Cycas taiwaniana
+	Leaflets longitudinally inserted at ca. 50° to rachis; apex of cataphylls with soft point; sterile blade of megasporophyll broadly ovate, obovate, or suborbicular; sclerotesta of seed smooth		11 Cycas szechuanensis
12 (9)	Trunk cylindric, 1-7 m; bark white-gray, gray, or brown, scaly or raised; pollen cones (25-)30-45 × 8-15 cm, microsporophylls 3.5-6 cm; megasporophylls 13-20 cm.		(13)
+	Trunk subterranean, base swollen; bark gray, smooth; pollen cones 20-30 × 6-8 cm, microsporophylls 1.5-3 cm; megasporophylls 8-14 cm.		(14)
13 (12)	Trunk often dichotomously branched toward apex, to 16 m, apex not tomentose; bark gray or white-gray, smooth toward base of trunk; leaflets with midvein sulcate adaxially and margin revolute to slightly recurved; seeds 4.5-6 × 4-4.7 cm		16 Cycas pectinata
+	Trunk simple, to 2(-3) m, apex densely tomentose; bark brown to dark gray, scaly; leaflets with midvein never sulcate adaxially and margin flat to slightly recurved; seeds 2.5-3.5 × 2.2-3 cm		8 Cycas panzhihuaensis
14 (12)	Leaflets longitudinally inserted at 55-65° to rachis; petiole with 9-16 spines along each side throughout length (SW Hainan)		14 Cycas changjiangensis
+	Leaflets longitudinally inserted at ca. 90° to rachis; petiole with 0-8(or more) spines along each side often only in apical part (W Guangxi).		(15)
15 (14)	Young leaves densely rusty brown tomentose abaxially; leaflets not overlapping, light green at maturity, 20-30 cm × 5-12 mm, base attenuate, margin strongly revolute		12 Cycas ferruginea
+	Young leaves sparsely red-brown tomentose abaxially; leaflets often overlapping, dark green at maturity, 10-18 cm × 14-18 mm, base usually truncate, margin flat or only slightly revolute		13 Cycas miquelii