Citation: L., Sp. Pl. 44 (1753).

Derivation: Latin from Greek kypeiros, some species of sedge.

Synonymy: Not Applicable

Common name: None

Description:
Annual or perennial herbs, sometimes with creeping often stoloniferous rhizomes; all leaves near the base of the stems, sometimes reduced to the sheaths, sometimes with many fine transverse septa which show as ridges on the surface (septate-nodulose).

Inflorescence terminal, capitate or umbel-like with simple or compound rays, rarely with rays distant from one another; spikelets spicate or digitate on the rays; each ray subtended by a persistent involucral bract; spikelets compressed, 1- to many-flowered; glumes in 2 opposite rows spirally arranged only in C. hamulosus; flowers all hermaphrodite or the terminal one sometimes male; rhachilla straight or flexuose, never prominently zig-zag, sometimes bordered by hyaline or coloured membranous wings; hypogynous bristles or scales absent; stamens 1-3; style branches 2 or 3.

Distribution:  About 600 species mainly in the tropics and subtropics. (A thorough study of the S.Aust. species is much needed and this key is very tentative).

Biology: No text

Key to Species:

1. Leaves reduced to membranous sheaths at the base of the stem, rarely the uppermost with a very short lamina
2. Style branches 2	C. laevigatus 19.
2. Style branches 3.
3. Involucral bracts 25-50 cm long, 8-15 mm broad	C involucratus 17.
3. Involucral bracts to 15 cm long, to 6 mm broad.
4. Stems cylindrical at the top, very faintly striate; involucral bracts pointed but not spinescent, usually at least 5, flat, at least 5 cm long; spikelets linear or oblong, 8-18 mm long.	C. vaginatus 28.
4. Stems trigonous at the very top, prominently striate; involucral bracts almost spine-tipped, 3 or 4, with incurved margins, usually less than 5 cm long, very rigid; spikelets ovate or lanceolate-ovate, 3-5.5 mm long	C. gymnocaulos 15.
1. Leaf blades present.
5. Glumes spirally arranged	C. hamulosus 16.
5. Glumes distichous.
6. Style branches 2.
7. Spikelets 1-flowered; rhizome creeping	C. brevifolius 5.
7. Spikelets several-flowered; plants tufted.
8. Nut dorsally flattened with a flat or concave face against the rhachilla; spikelets swollen, greenish	C. pygmaeus 22.
8. Nut laterally flattened, equally biconvex with one edge next to the rhachilla; spikelets flat, blackish	C. sanguinolentus 25.
6. Style branches 3.
9. Rhachilla prominently winged.
10. Inflorescence a single head of crowded more or less sessile green spikelets	C. pygmaeus 22.
10. Inflorescence variously compound, if occasionally a single head then the spikelets darkly pigmented.
11. Glumes to 2.5 mm long.
12. Spikelets in spikes at the end of the rays	C. exaltatus 12.
12. Spikelets subumbellate or in globose heads on the ends of the rays.
13. Plants less than 30 cm high; spikelets 2-2.5 mm broad	C. rotundus 24.
13. Plants usually more than 50 cm high; spikelets 1-2 mm broad.
14. Spikelets 8-14-flowered	C. gunnii 14.
14. Spikelets usually 20-50-flowered.
15. Spikelets to c. 1.2 mm broad, in clusters of 1 -6; leaves and bracts with 3 white veins	C. albostriatus 1.
15. Spikelets 1.5-2 mm broad, in clusters of usually more than 6; leaves and bracts not white- nerved	C. dactylotes 9.
11. Glumes 3-5 mm long.
16. Spikelets 2.5-4 mm broad.
17. Spikelets arranged spicately on the ultimate branches of the inflorescence	C. bifax 4.
17. Spikelets arranged digitately on the ultimate branches of the inflorescence	C. gilesii 13.
16. Spikelets 1-2 mm broad.
18. Spikelets 15-50 in each head or spike.
19. Leaves and bracts smooth	C. congestus 7.
19. Leaves rough with short shallow lateral ridges (septate-nodulose)	C. lucidus 21.
18. Spikelets up to 10 in each head or spike.
20. Inflorescence corymbose or spicate, the involucral bracts with their rays (if any) prominently separated from one another	C. bulbosus 6.
20. Inflorescence umbel-like or a compound head, the involucral bracts and rays very close together
21. Stems cylindrical except near the top; lower involucral bract often suberect at the base; umbel-rays often curved; glumes acute in profile; nut developed	C. victoriensis 29.
21. Stems prominently 3-angled throughout; involucral bracts spreading; rays straight; glumes narrowly rounded in profile at the tip; nut not maturing	C. rotundus 24.
9. Rhachilla not winged (species with slightly developed wings are included under both leads)
22. Nut less than half as long as the glumes which have prominent recurved points; plants curry-scented when dry	C. squarrosus 26.
22. Nut more than half as long as the glume; plants not curry-scented when dry
23. Nut broadly obovate or elliptic, with acute angles and concave sides, not more than 1.5 mm long; annuals, sometimes small
24. Inflorescence of up to 4 spikelets in a single apparently lateral cluster	C. tenellus 27.
24. Inflorescence of usually numerous spikelets, terminal and often compound
25. Inflorescence a dense head often less than 5 mm diam., partly concealed by the bracts; stems less than 10 cm long	C. pygmaeus 22.
25. Inflorescence compound; stems usually more than 15 cm long
26. Spikelets 2-3 mm broad, pallid or greenish	C. eragrostis 11.
26. Spikelets 1-2 mm broad, yellow or reddish
27. Spikelets to 8 mm long, in dense heads at the ends of the rays; glumes a dark red-black	C. difformis 10.
27. The longest spikelets more than 8 mm long, in short but distinct spikes at the ends of the rays; glumes yellow to brown	C. iria 18.
23. Nut narrowly oblong to linear or somewhat obovoid-oblong, usually more than 1.5 mm long, with the angles more or less rounded and the sides flat to convex; mostly perennials
28. Umbel-rays to 14 cm long; spikelets 1.2-2 mm wide; glumes not more than 2 mm long	C. dactylotes 9.
28. Umbel-rays rarely to 10 (to 15 in C. alternifiorus) cm long; spikelets usually more than 2 mm wide; glumes usually more than 2.5 mm long
29. Rhizomes long; inflorescence a dense simple head.	C. arenarius 3.
29. Rhizomes 0 or very short; inflorescence usually compound.
30. Nut dorsally flattened with a flat or concave face against the rhachilla	C. pygmaeus 22.
30. Nut trigonous
31. Glumes 4-5 mm long, with recurved mucros	C. gilesii 13.
31. Glumes less than 4 mm long, shortly mucronate.
32. Plants usually less than 25 cm high; anthers 0.3-1.1 mm long including any apical appendage	C. rigidellus 23.
32. Plants usually more than 30 cm high; anthers 1.1-2.5 mm long including any apical appendage.
33. Leaves not septate-nodulose; glumes 2.7-3.8 mm long
34. Plants tufted or very shortly rhizomatous (but always forming a tussock)	C. sp.aff.cunninghamii 8.
34. Plants distinctly rhizomatous (culms solitary at each node)	C. lhotskyanus 20.
33. Leaves septate-nodulose; glumes 2.2-3.5 mm long	C. alterniflorus 2.

Author: Not yet available