Scientific Name:
Cirsium Mill., Gard. Dict. Abr. (ed. 4) , 334 (1754)

Biennial or perennial herbs, rarely annual.  Stems winged or not.  Hairs bristly, or soft and multicellular, or cobwebby.  Lvs alternate, sessile, entire or pinnatifid or pinnatisect, dentate;  lobes and teeth spine-tipped.  Capitula homogamous, cylindric, ovoid or globose, solitary or in corymbs or clusters. Involucral bracts in several series, deltoid, lanceolate or linear;  hairs cobwebby or 0;  outer bracts usually spine-tipped, often spreading.  Receptacle flat; scales numerous, setaceous.  Florets ☿ or unisexual, all tubular.  Corolla glabrous, 5-lobed, usually purple, sometimes white or yellow. Anthers acute at apex, with basal appendages 0.5–1.5 mm long;  filaments ciliate.  Style branches linear, erect, appressed.  Achenes obovoid, weakly flattened, glabrous, smooth;  achene insertion basal;  pappus hairs in several rows, soft, silvery, plumose, united at base into a ring.

[From:  Webb et al. (1988) Flora of New Zealand. Volume 4.]

Number of species in New Zealand within Cirsium Mill.
Exotic: Fully Naturalised4
Mabberley, D.J. 2008: Mabberley's plant book, a portable dictionary of plants, their classification and uses. Edition 3. Cambridge University Press.
Miller, P.: The Gardeners Dictionary. Edition 4. London.