Key to sections

1	Each cladoprophyll with a developed female flower inside; inflorescence spicate; spikes numerous and densely arranged.		1 C. sect. Japonicae
+	Cladoprophylls without flowers or some with flowers; inflorescence paniculate or racemose, if inflorescence spicate then spikes fewer		(2)
2 (1)	Cladoprophyll below terminal spike with a developed female flower inside, others without flower; rachilla present at base of nutlet; inflorescence racemose		(3)
+	Cladoprophylls without flowers; rachilla absent; inflorescence paniculate or spicate		(4)
3 (2)	Terminal spike androgynous; utricle with smooth straight beak; nutlets with flat faces.		2 C. sect. Mundae
+	Terminal spike male; utricle with scabrous geniculate beak; nutlets with concave faces.		3 C. sect. Hangzhouenses
4 (2)	Inflorescence spicate; spikes fewer, densely arranged in capitate spicate inflorescence.		10 C. sect. Scabrellae
+	Inflorescence paniculate		(5)
5 (4)	Spikes unisexual, male ones at upper parts of inflorescence branches, female ones at lower parts.		9 C. sect. Hypolytroides
+	Spikes bisexual, androgynous		(6)
6 (5)	Culm lateral; cauline leaves reduced and spathelike; involucral bracts spathelike		(7)
+	Culm central; cauline leaves well developed and leafy; involucral bracts leafy		(8)
7 (6)	Radical leaves fasciated, leaf blades elliptic to linear-elliptic.		7 C. sect. Hemiscaposae
+	Several radical leaves forming a high shoot, leaf blades linear.		8 C. sect. Surculosae
8 (6)	Leaf blades and involucral bracts elliptic to linear-elliptic, with prominent transverse veins; inflorescence branches with fewer spikes.		6 C. sect. Euprepes
+	Leaf blades and involucral bracts linear, without transverse veins; inflorescence branches bearing numerous spikes, very rarely bearing few spikes		(9)
9 (8)	Spikes cylindric, larger, 2-8 cm, with numerous spikelets.		4 C. sect. Polystachyae
+	Spikes oblong, smaller, less than 2 cm, with fewer spikelets.		5 C. sect. Indicae