1	Female flowers without bracteoles; female part of spikes connected with or separated from male part		(2)
+	Female flowers with bracteoles; female part of spikes separated from male part		(6)
2 (1)	Female part of spikes not separated from male part		(3)
+	Female part of spikes separated from male part		(4)
3 (2)	Stigmas spatulate; hairs on stalk of female flowers ca. as long as style.		1 T. orientalis
+	Stigmas lanceolate; hairs on stalk of female flowers shorter than style.		2 T. latifolia
4 (2)	Stigmas linear, slender; axis of male part in spikes with brown hairs, hairs furcate or not.		3 T. przewalskii
+	Stigmas spatulate; axis of male part in spikes with whitish or yellowish brown hairs, hairs not furcate		(5)
5 (4)	Stems 1.5-2 m tall; hairs on stalk of female flowers shorter than style.		4 T. changbaiensis
+	Stems 0.8-1.3 m tall; hairs on stalk of female flowers ca. as long as style.		5 T. laxmannii
6 (1)	Stems less than 0.8 m, with sheathlike leaves at base		(7)
+	Stems more than 1 m, without sheathlike leaves		(9)
7 (6)	Axis of male part in spikes with hairs; leaves 2-4 mm wide.		12 T. lugdunensis
+	Axis of male part in spikes without hairs; leaves 1-2 mm wide		(8)
8 (7)	Hairs on stalk of female flowers swelling at tip, shorter than style.		10 T. minima
+	Hairs on stalk of female flowers not swelling at tip, ca. as long as style.		11 T. pallida
9 (6)	Bracteoles spatulate or subtriangular; stigmas lanceolate (to linear).		9 T. davidiana
+	Bracteoles not spatulate; stigmas linear to lanceolate		(10)
10 (9)	Leaves abaxially carinate, transverse section triangular; bracteoles linear.		6 T. elephantina
+	Leaves abaxially convex, transverse section semicircular; bracteoles filiform to triangular		(11)
11 (10)	Anthers ca. 2 mm; stigmas ca. as broad as styles.		7 T. angustifolia
+	Anthers ca. 1.4 mm; stigmas broader than styles.		8 T. domingensis