1	Plants 22-55 cm; leaves equalling stem, 2.5-5.5 mm wide; glumes widely cymbiform, red-brown, glossy.		4 C. sanguinea
+	Plants (30-) 40-150 cm; leaves mostly longer than stem, 4-10 mm wide; glumes not widely cymbiform, red-brown and glossy.		(2)
2 (1)	Plants to 1.5 m; female glumes 2.5-4 mm; utricles 3-4.5 mm, beak 0.7-1 mm.		3 C. myosurus
+	Plants up to 90 cm; female glumes 1.8-3 mm; utricles 3.3-4 mm, beak 1-1.5 mm.		(3)
3 (2)	Plants 30-70 cm; leaves 5-7 mm wide; utricles 3.3-4 mm, tightly clasping nut, glossy.		1 C. filicina
+	Plants 40-90 cm; leaves 4-10 mm wide; utricles 3.5-4 mm, slightly inflated, not glossy.		2 C. cruciata