C. dioica: creeping, dioecious, grass-like, 6-8 inches high; female spikes shorter, ovoid. - Spongy bogs. Fl. May, June.
** Spikelets arranged in a compound continuous or interrupted spike; stigmas 2.
† Rootstock creeping.
C. intermedia: stems 1-2 feet high; spikelets large ovoid, simple, crowded into a terminal spike. - Wet meadows. Fl. May.
†† Bootstock tufted.
C. vulpina: stems 2-4 feet high; spikelets numerous, densely crowded into a terminal spike, interrupted at the base. - Wet places. Fl. May, June.
C. stellulata: stems 6-12 inches high; spikelets three or four, oval-oblong or roundish, rather distant; bracts not leaflike. - Boggy places. Fl. May, June.
*** Spikes separate, one or more terminal ones wholly (rarely partially) barren, the rest fertile.
† Beak of 'thefruit entire, emarginate or shortly 2-toothed.
‡ Nut plano-convex; stigmas 2; barren spikes one or more.
C. acuta; stems 2-3 feet high; spikes cylindrical, dark-coloured, the fertile 3 inches long or more; glumes narrow and pointed. - Wet places. Fl. May, June.
C. vulgaris: stems 1 foot high; spikes oblong, 1/2-2 inches long, dark-brown; glumes blunt. - Marshes. Fl. May, June.
‡‡ Nut three-cornered; stigmas 3. (a) Fruits smooth; barren spikes terminal, solitary.
C. panicea: stem 1-2 feet high; fertile spikes about two, erect, cylindrical, 1/2-1 inch long, loosely imbricated. - Carnation Grass. - Marshy places. Fl. May, June.
(b) Fruits smooth; barren spikes terminal, several.
C. pendula: stems 3-6 feet high; fertile spikes drooping, 4-6 inches long, cylindrical, densely flowered. - Damp woods. Fl. May.
C. glauca: stems 1/2-1 1/2 fertile spikes two or three, 1/2-1 inch long, more or less drooping; fruit slightly scabrous. - Damp places. Fl. May, June.
(c) Fruits downy.
C. prsecox: stem 1/4 - 1 foot high; barren spike solitary, fertile spikes one to three, oblong-ovate, near together, sessile, or the lowermost sometimes slightly stalked; lowest bract shortly sheathing, with a leafy point. - Dry heaths. Fl. April, May.
C. pilulifera: stems ½ - 1 foot high barren spike solitary; fertile about three, roundish, nea;r together, sessile; lowest bract with a leafy point, sheathless. - Wet heaths. Fl. May.
†† Beak of the fruit long, 2-toothed or bifid; (nut three-cornered: stigmas 3).
‡ Bracts sheathing, leaf-like; beak of the fruit planoconvex.
C. flava: stems 6-12 inches high; barren spike solitary, cylindrical; fertile ones about three, roundish-oval, subsessile, near the barren, and often one lower down on a longish stalk. - Wet places. Fl. May, June.
C. sylvatiea: stem two feet high; barren spike solitary; fertile about four, distant, drooping, linear. - Damp woods. Fl. May.
C. hirta: stem 1 1/2-2 feet high; barren spikes two or three: fertile ones two or three, remote, erect, oblong-cylindrical, stalked. - Hammer-sedge. - Damp places. Fl. April.
‡‡Bracts not sheathing; beak of the fruit terete.
C. ampullacea: stem 1-2 feet high; barren spikes several; fertile ones 2-4, remote, cylindrical, erect, stalked; fruit inflated, abruptly contracted into a long beak. - Wet bogs. Fl. May, June.
C. vesicaria: stem 2 feet high; barren and fertile spikes nearly as in the last, but rather shorter; fruit inflated, gradually tapering into a short beak. - Wet bogs. Fl. May.
C. riparia: stem 3 feet high; barren spikes several; fertile two or three, rather distant, cylindrical, 2-3 inches long; fruit much flattened or convex on both sides narrowed into a short broad beak. - Watery places. Fl. April, May.