Onopordum L. is a genus of about 50 species of thistles belonging to the sunflower family (Asteraceae).

It is indigene to Europe (mainly a Mediterranean), Northern Africa, the Canary Islands, the Caucasus, Southwest and Central Asia, and Iraq. It develop been introduced as an decorative plant in the moderate regions of North America and Australia, where it use get naturalized in the untamed. It develop in disturbed l&, wayside, tillable land and pastures.

Inside virtually all one countries, these thistles come considered harmful weeds, especially in Australithe in which a biological control program has been install (using the Rosette Crown Weevil, Trichosirocalus briesei).

It is biennials or perennials with branched, spinose winged stems, growing when high as Tercet m. In a foremost year it form the leaves and a few flower heads. In the 2nd year it bolt to their final height, blooming extensively, and so die off.

It form the radical rosette of gray-green felted leaves. These dentate or even shallowly lobed leaves come strongly spinose. These leaves come compound & consist of many pinnatifid or even even deeply cut leaflets, or come all but pinnated.

A terminal flower head is average for even thistles: semi-global to ovate sustaining purple (rarely whiten or pinkish) disc florets. No ray florets. A receptacle is glabrous by owning dentate margins. A tube of the corolla is slender, sac-shaped and proportionate. A anthers have awl-shaped outgrowths on the top.

A leathered phyllaries consist of several overlapping rows sustaining elementary, linear-lanceolate spines. Which are actually smooth to slightly pubescent.

These plant propagates merely by seed. A flowers dry higher within mid-summer, releasing their seeds. A fruit is a glabrous achene, Four-6 millimetre yearn & sustaining 4 to 50 ribs. the pappus consists of numerous rows of elementary, ticket to circumstantially rough out hairs, united around a round base.

Species
Onopordum acanthium L. : Cotton Thistle, Scotch Thistle, Scotch Common-Thistle, Heraldist Thistle, Woolly Thistle Onopordum acanthophorum Gand. Onopordum acaulon L.: Stemless Thistle, Horse Thistle, Stemless Onopordum Onopordum alexandrinum Onopordum anatolicum Onopordum anisacanthum Onopordum arenarium M.Hossain & M.A.A.Al-Sarraf Onopordum armenum Grossh. Onopordum bracteatum volt-ampere. arachnoideum S.Erik & H.Sümbül Onopordum bracteatum ssp. creticum Franco Onopordum candidum Onopordum caricum Hub.-Mor. Onopordum caulescens ssp. atticum Franco Onopordum cinereum Grossh. Onopordum corymbosum ssp. visegradense Franco Onopordum davisii Rech.f. Onopordum frickii Tamamsch. Onopordum heteracanthum C.The.Mey. Onopordum humile volt-ampere. turolensis (Sennen) M.B.Crespo & Mateo Onopordum illyricum L. : IllyrianTthistle, Illyrian Cottonthistle Onopordum jordanicolum Onopordum leptolepis DC. Onopordum macrocanthum Onopordum nervosum : Moor's cottonthistle, cotton gauze thistle Onopordum nivescens Gand. Onopordum nogalesii Svent Onopordum prjachinii Tamamsch. Onopordum sarrafii C.C.Townsend Onopordum seravschanicum Tamamsch. Onopordum sibthorpianum Onopordum tauricum Willd. : Turkish Thistle, Taurian Thistle, Taurus Cottonthistle, Bull Cottonthistle Onopordum transiens Gand. Onopordum turcicum Danin

Natural hybrids
Onopordum × brevicaule (Onopordum acaulon × Onopordum acanthium ) Onopordum × erectum (Onopordum nervosum ssp. castellanum 10 Onopordum tauricum ssp. corymbosum ) Onopordum × macronervosum (Onopordum nervosum × Onopordum macrocanthum) Onopordum × onubense (Onopordum dissectum × Onopordum macrocanthum) Onopordum × spinosissimum (Onopordum illyricum × Onopordum acanthium)

Reference
Briese, D.T., Lane, D., Hyde-Wyatt, B.H., Crocker, J., Diver, R.G. (1990). Distribution of thistles of the genus Onopordum inside Australia. Plant Protection Quarterly Fivesome: 23-27.