Thistle

Thistle, a popular name applied to a number of spinous herbaceous plants, mostly Compositae. Though the ligulifloral genus Sonchus is known as sow-thistle, the thistles proper are almost co-extensive with the tubulifloral tribe Cynareae, which is characterised by scattered leaves, usually spinous-toothed; an involucre often globose and of spinous bracts; and the flowers all tubular and generally bisexual. Onopordum Acanthium is known as the Scottish thistle, a title more applicable to Carduus lanceolatus; Carthamus tinctorius is sometimes called "saffron thistle" [SAFFLOWER]; and the globe artichoke (Cynara Scolymus) is practically a thistle; but most thistles belong to the genus Carduus, and are characterised by having several rows of long feathery hairs in the sessile pappus which constitutes "thistle-down" and which rapidly disperses these deep-rooted and troublesome weeds over agricultural land.