The Probert Encyclopaedia of Nature

THISTLE

Thistle is a name popularly applied to many prickly plants, but is strictly applied to those of the genus Carduus, of the family Compositae. Members of the Carduus genus are perennial or biennial herbs, forming large rosettes of spiny leaves the first year, and developing prickly stems the second year. The flowers are small, red or purple in colour, tubular, massed in an oval or roundish head, which is invested in over-lapping, rigid and spiny bracts. The seeds each have a tuft of silky hairs, known as thistledown, attached to them which allow for wind distribution.
Research Thistle