Centaurea
(from Kentaurion, the name given by Dioscorides to the Centaury, Erythroea Centaurium, which was said to have cured a wound in the foot of the centaur Chiron, caused by the arrow of Hercules). Centaury. ORD. Compositoe. Pappus short and bristly, rarely none; involucre globose or oblong; bracts imbricated, scarious, fringed, toothed, or spinous; receptacle bristly; florets all tubular, the outer ones sometimes large and neuter. Of this genus, about four hundred species (annuals, biennials, and perennials) have been described; comparatively few, however, are worth growing, but these are of the easiest culture in ordinary soil. Seeds of the annual kinds may be sown in the open border, in April, and the plants subsequently thinned out to three or four in a patch, where they are to remain and flower. The biennials may be sown in March, in a slight heat, and planted out in May. The herbaceous perennials require merely ordinary care and attention, and common garden soil, wherein to thrive well. C. ragusina and C. Cineraria are very extensively cultivated, and as failures are occasionally experienced in their propagation, the following plan, practised by a successful grower, is recommended: First, make the cuttings, about the beginning of September, take off the bottom leaves, and allow only about 1in. of wood to remain. Insert them in 60-sized pots, in a compost of loam, leaf mould, and sharp sand, in equal proportions; plunge in a cold frame, and keep them close for about four weeks, by which time they will be rooted. Great care must be taken in watering. When they become pot-bound, shift into 48-sized pots, in which they may remain until bedding-out time. Seeds may also be easily procured and raised. They should be sown in August, in slight heat; and when the seedlings are large enough to handle, they should be potted off singly into small thimble pots, in which they may be kept through the winter, in a cold frame or cool house, a shift being given in the spring. Much stronger plants are thus obtained than if the seed is sown in the early part of the year.
C. alpina (alpine).* fl.-heads yellow; involucral scales egg-shaped, obtuse. July. l. decurrent, spinous, downy beneath. h. 3ft. Southern and Eastern Europe, 1640. Hardy herbaceous.
C. americana (American). fl.-heads red; outer scales of involucre three times as short as their appendages; peduncles ventricose at top. August. l. oblong, membranous, entire. h. 3ft. North America, 1824. Hardy annual. C. atropurpurea (dark purple).* fl.-heads dark purple; involucral scales ovate-lanceolate, serrate, ciliated. June to August. l. bipinnatifid; segments lanceolate. h. 3ft. Eastern Europe, &c., 1802. Hardy perennial. C. aurea (golden).* fl.-heads golden-yellow; involucre simply spinous; spreading; florets equal. July to September. l. hairy; lower ones pinnatifid. h. 2ft. South Europe, 1758. Hardy perennial. (B. M. 421.) C. babylonica (Babylonian).* fl.-heads yellow, small, numerously produced close to, and along the stem. July. l., root ones lanceolate-ovate, stalked, with a few small teeth; stem ones narrower, lanceolate, decurrent; large, clothed with a white cottony down, which renders this species peculiarly well adapted for borders and margins of shrubberies. h. 6ft. to 10ft. Levant, 1710. Hardy perennial.
C. candidissima (whitest). A synonym of C. Cineraria. C. Cineraria (Cineraria). fl. purple; involucre ciliated. July and August. l. downy, very white, all compound; lowest bipinnatifid; upper ones pinnate-laciniated. h. 3ft. Italy, &c., 1710. Half-hardy herbaceous perennial. SYN. C. candidissima.
C. Cyanus (dark blue).* Blue-bottle, Bluet, or Cornflower. fl. heads, florets of the disk purple, small; of the ray, bright blue, few, larger, spreading; scales of the involucre greenish, with brown margins. July. l. linear, entire; the lower ones often toothed; cottony. h. 2ft. to 3ft. Britain. This is one of the showiest of blue-flowered annuals. It varies in all shades from white to deep rose.
C. dealbata (whitened).* fl.-heads rose-coloured. Summer. l. smooth above, and covered with white hairs underneath; radical ones stalked, pinnate, with obovate lobes, coarsely toothed, often auricled at the base; stem ones pinnate, with oblong. lanceolate lobes. h. 1ft. to 1 1/2ft. Caucasus, 1804. Hardy herbaceous.
C. depressa (depressed). fl.-heads blue, with brownish-red centre. Summer. Orient, 1818. h. 1ft. This species resembles C. Cyanus, but is a dwarfer grower, and has brighter-coloured flowers. Hardy herbaceous. (B. M. 3662.) C. stricta comes very near this, if indeed, anything more than a dwarf variety. C. Fenzlii (Fenzl's).* fl.-heads canary-yellow, large, terminal; flower-stems erect, branching from the base. l. large, handsome, cordate-ovate, glaucous green, radical. h. 4ft. Armenia, 1868. Hardy biennial. (B. M. 6392.) C. macrocephala (large-headed).* fl.-heads yellow, larger than most other; scales of involucre jagged. July. l. oblong-lanceolate, shortly decurrent, undivided, rough, somewhat serrated, ending in a short sharp point. Stem simple, hollow, and thickened under the flower. h. 3ft. Caucasus, 1805. Hardy perennial. (B. M. 1248.) C. montana (mountain).* fl.-heads blue, large, handsome; florets deeply cut into four or five segments. Early summer. l. lanceolate, entire, decurrent, cottony. Stem usually simple, sometimes sparingly branched. h. 2ft. Europe, 1596. Hardy perennial. (B. M. 77.) There are also white-flowered (alba) and rose-coloured (rosea) varieties, both of which are well worth growing. C. moschata (musky). Sweet Sultan. fl.-heads purple; involucre roundish, smooth; scales egg-shaped. July. l. lyrate-toothed. h. 2ft. Persia, 1629. Hardy annual.
C. pulchra (beautiful). fl.-heads bright purple, globose; outer scales of involucre drawn out into an ovate, pectinately ciliated, scabrous appendage; middle bristle longer, stiffer and shining. August. l. sessile, glabrous, pinnate; lobes linear, acute, entire or a little toothed. Stem branched, furrowed. h. 1ft. Cashmere, 1838. Half-hardy. (B. R. 26, 28.) C. ragusina (Ragusan).* fl.-heads yellow; involucre ciliated. June, July. l. downy with silvery hairs, pinnatifid; segments obtuse, egg-shaped, quite entire, outer ones largest. h. 2ft. Candia, 1710. Half-hardy perennial. (B. M. 494.) C. ruthenica (Russian). fl.-heads pale yellow; involucre scales egg-shaped, obtuse. July. l. pinnate, smooth; leaflets cartilaginous, sharply serrate; terminal one oblong, egg-shaped. h. 3ft. Orient, 1806. Hardy perennial. C. suaveolens (sweet-scented).* Yellow Sultan. fl.-heads yellow, sweet-scented; involucre round, smooth. July. l. lower ones broad, somewhat spathulate, toothed; upper ones lyrate at base. h. 1 1/2ft. Levant, 1683. Hardy annual. (S. B. F. G. i. 51.) C. uniflora (one-flowered). fl.-heads purple, roundish, terminal, nearly sessile among the upper leaves. Summer. l. small, white and downy; lower ones oblong-lanceolate, toothed; upper ones lanceolate, entire. h. 9in. to 15in. South Europe, 1824. Hardy perennial.