Genus: Cirsium
Genus description:
Spiny, biennial or perennial herbs, rarely annuals. Leaves alternate, entire to pinnatisect, with spinulose margin or upper surface and usually spiny teeth or lobes. Involucral bracts imbricate, often with a vitta (resin gland), usually with a simple apical spine. Receptacular scales numeruos, setaceous. Florets hermaphrodite, rarely unisexual, purple or yellowish, rarely white. Anthers with basal appendages 0.3-1.5 mm. Achenes oblong, gibbous, compressed, the truncate apex with a distinc, annular margin surrounding a subconical central projection. Pappus of several rows of plumose setae, the inner somewhat longer than the outer and simple, often flattened, lanceolate an ciliate towards the apex, the paapus of outermost florets with fewer, simple setae.Morphological intermediates, which are probably hybryds, are frequent in the genus. (..)
Measurements of the diameter of the invulcre refer to the middle of the capitulum, excluding the patent apices of the bracts.
In most of the species with purple florets, white variants are occasionally found.
Species and images:
