Cirsium Mill.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Herbs with spiny wings on stems

Morphology Leaves

Leaves alternate, pinnatifid (in Somalia), with spine-tipped teeth

Morphology Reproductive morphology Inflorescences

Capitula homogamous, discoid; phyllaries many, in several series, usually spine-tipped

Morphology Reproductive morphology Flowers Florets

Florets slender

Morphology Reproductive morphology Flowers Gynoecium Style

Style with an abrupt swelling with a ring of hairs just below the branches, these flat and±connate, diverging only distally

Morphology Reproductive morphology Fruits

Achenes with a raised annular collar; pappus many-seriate, of plumose bristles connate into a ring at the base.

Distribution

Some 450 species, mainly in north temperate regions, with several widespread weeds (thistles).

Compositae, G. V. Pope. Flora Zambesiaca 6:1. 1992

Morphology General Habit

Perennial or biennial (annual) herbs.

Morphology Stem

Stems spiny-winged from decurrent leaf bases, rarely unarmed.

Morphology Leaves

Leaves pinnatifid in the Flora Zambesiaca area (entire) with spine-tipped teeth at the margins.

Morphology Reproductive morphology Inflorescences Capitulum

Capitula homogamous, discoid, loosely aggregated (or large solitary and terminal) on the branches.

Morphology Reproductive morphology Inflorescences Bracts Phyllaries

Phyllaries numerous many-seriate imbricate appressed, ± patent apically and usually spine-tipped, with or without subterminal vitta, margins entire to spinulose or lacerate.

Morphology Reproductive morphology Flowers Receptacle

Receptacle flat or convex, densely long-setose.

Morphology Reproductive morphology Flowers Florets

Florets hermaphrodite (rarely unisexual); corollas white to purple (yellowish), narrowly tubular with a broad deeply 5-lobed limb.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anther bases sagittate, the adjacent auricles connate and produced into entire or lacerate tails.

Morphology Reproductive morphology Flowers Gynoecium Style

Style 2-branched, with an abrupt swelling below the branches and a ring of hairs at or below the swelling; the branches erect, long somewhat flat and ± connate, diverging only near the tips.

Morphology Reproductive morphology Fruits

Achenes ± oblong, compressed smooth, glabrous with a raised annular collar at the apex, attachment-scar sub-basal oblique or ± horizontal.

Morphology Reproductive morphology Seeds

Pappus many-seriate; setae plumose, connate into a ring at the base, deciduous (± persistent), longest in the innermost series.

Ghazanfar, S. A., Edmondson, J. R. & Hind, D. J. N. (Eds). (2019). Flora of Iraq, Volume 6: Compositae.Kew Publishing

Morphology General Habit

Biennial or perennial, very rarely annual herbs, with stems winged from the decurrent leaves or not

Morphology Leaves

Leaves simple or more commonly pinnately lobed or divided, spinous with rather weak to extremely strong spines, often ± cottony-arachnoid at least on lower surface, upper with or without setae or spinules

Morphology Reproductive morphology Inflorescences Capitulum

Capitula solitary or in corymbs, racemes or dense clusters, homogamous, hermaphrodite or rarely dioecious; phyllaries multiseriate, closely imbricate at least below, glabrous to ± floccose, outer and median ± spine-tipped with spines erect to squarrose, margins entire to spinulose or fimbriate; receptacle long-pilose

Morphology Reproductive morphology Flowers Corolla

Corollas all tubular, usually pink to purple, sometimes white or yellow, limb usually divided to about halfway but sometimes deeper

Morphology Reproductive morphology Fruits

Achenes smooth, glabrous, compressed to subterete; pappus multiseriate, connate into a ring at base, usually deciduous, innermost hairs often only scabrid at apex and ± clavate.

Distribution

Probably about 250 species in the northern temperate and subtemperate regions.

Etymology

Cirsium (from Gr. Κιρσιον, kirsion, a kind of thistle, in turn from Κιρσος, kirsos, ‘a swollen vein or welt’, because thistles were often used as a remedy against such things).