* Involucral bracts not prickly.
C. nigra: stems erect, hard, branched, 1-2 feet high; leaves linear-lanceolate or oblong, the upper ones entire or nearly so, the lower with a few coarse teeth; involucres globular, on terminal peduncles, the bracts closely imbricate, so as only to show their appendages, which are brown or black, and deeply fringed, except on the innermost, where they are shining and jagged; florets purple, all equal or the outer row much larger and neuter; fruits crowned by a ring of very minute, scaly bristles, occasionally intermixed with a few longer, very deciduous ones, - Knapweed. - Meadows, pastures, and waysides. Fl. June to August.
Var. Jacea: appendages of the involucral scales much paler, with a much shorter fringe, or jagged. - Sussex, rare.
C. Scabiosa: stem 2-3 feet high, stoutish, branched at the base; leaves deeply pinnatifid, with linear or lanceolate lobes, oi ten coarsely-toothed or lobed; flower-heads large, with purple florets, the outer ones always enlarged and neuter; involu-cral bracts broad, bordered only with a black appressed fringe, leaving the green centre exposed; pappus of stiff hairs or bristles nearly as long as the achene. - Pastures, waste places, roadsides, etc. Fl. July to September.
C. Cyanus: annual; stems erect, branching, two feet high, cottony; leaves narrowish, the lower ones toothed, the upper linear and entire; involucres solitary, on long terminal peduncles, ovoid, the bracts appressed, bordered by a fringe of very small teeth; central florets bluish purple, the outer ones much larger, bright blue. - Cornflower or Bluebottle. - A cornfield weed. Fl. June to August. In our gardens where this plant is cultivated as an annual flower, it yields various colours.
** Involucral bracts ending in a long stout prickle.
C. Calcitrapa: annual; stems somewhat cottony, spreading or prostrate, seldom above a foot high; leaves pinnatifid, with a few long linear or lanceolate lobes; flower-heads sessile among the upper leaves or in the forks of the branches, not large, the florets purple; involucral bracts ending in stiff spreading spines, with 1-2 smaller prickles at their base; achenes without any pappus. - Waste places and roadsides, most abundant near the sea. Fl. July, August.