Onopordon
(the old Greek name, said by Pliny to be derived from onos, an ass, and pordon, crepitus; on account of its effect upon the asses who eat it). Sometimes spelt Onopordum. Cotton Thistle. ORD. Compositae. A genus comprising about a dozen species of hardy annual, biennial, or perennial herbs, sometimes tall and branched, with decurrent, winged stems, sometimes almost stemless. They are natives of Europe, North Africa, and Western Asia. Flower-heads purplish, violet, or white, large; involucre globose or broad; receptacle flat, fleshy; achenes glabrous. Leaves radical or alternate, pinnatifid or sinuate-toothed. Two or three species of this genus are grown for their stately habit, and large and showy flowers. They will generally thrive in almost any ordinary garden soil, and are more especially adapted for the rougher parts of the subtropical garden. Seeds should be sown, in moderately good and well-drained soil, in early spring.
O. Acanthium (Acanthium).* Common Cotton Thistle. fl.-heads purple, large; scales of the calyx subulate, spreading in every direction. July. l. oblong, inclining to ovate, woolly on both sides. Stem branched, woolly. h. 4ft. to 5ft. Europe (Britain), Siberia. A very handsome perennial, with a bold habit and vigorous growth. (F. D. 909; Sy. En. B. 680.)
O. arabicum (Arabian). fl.-heads purple. l. having both sides covered with a white down. Stem also woolly, slightly branching, erect. h. 8ft. South Europe, 1686. Biennial. (B. M. 3299.)
O. elongatum (elongated). A synonym of O. illyricum. O. illyricum (Illyrian). fl.-heads purple. July. l. decurrent, narrow-oblong-lanceolate, spiny-toothed, uppermost ones very short. h. 6ft. South Europe, 1640. A fine biennial species, with the general appearance of O. Acanthium, but having greener, more deeply-cut, and more spiny leaves, stiffer stem, and a more branching habit. SYN. O. elongatum.
O. macracanthum (long-spined). fl.-heads purple; involucre somewhat tomentose. July. l. decurrent, narrow-oblong-lanceolate, acuminate, spiny-toothed, glabrous above, cobwebby beneath. Stem erect, branched at apex, cobwebby. h. 6ft. Barbary, 1798. Annual. (S. F. G. 832.)