Carduus

Linnaeus
Sp. Pl. 2: 820. 1753.
,
Gen. Pl. ed. 5, 358. 1754.
Common names: Plumeless thistle chardon
Etymology: From ancient name of thistlelike plant
Treatment appears in FNA Volume 19. Treatment on page 91. Mentioned on page 57, 66, 83, 96, 97, 122.

Annuals or biennials [perennials], 30–200(–400) cm, spiny, ± tomentose, sometimes glabrate. Stems erect, simple to much branched, (spiny-winged). Leaves basal and cauline; petiolate or sessile; blade margins spiny dentate, often 1–2-pinnately lobed, faces glabrous or hairy, eglandular. Heads discoid, borne singly or 2–20 in dense clusters or corymbiform arrays. (Peduncles naked or leafy-bracteate, spiny-winged or not winged.) Involucres cylindric to spheric. Phyllaries many in 7–10+ series, linear to broadly ovate, bases appressed, margins entire, apices ascending to spreading or reflexed, acute, spine-tipped. Receptacles flat, epaleate, bearing setiform scales (“flattened bristles”). Florets several–many; corollas white to pink or purple, ± bilateral, tubes long, slender, throats short, campanulate, abruptly expanded from tubes, lobes linear; anther bases sharply short-tailed, apical appendages oblong; style branches: fused portions with slightly, minutely puberulent, swollen basal nodes, distally papillate or glabrous, distinct portions very short. Cypselae ovoid, slightly compressed, faces smooth, glabrous, attachment scars slightly lateral; pappi persistent or falling in rings, of many minutely barbed, basally connate bristles or setiform, minutely barbed scales (“minutely flattened bristles”). x = 8, 9, 10, 11, 13.

Distribution

Introduced; Eurasia, Africa.

Discussion

Species ca. 90 (5 in the flora).

Key

1 Phyllary appendages 2–7 mm wide, usually wider than appressed bases; peduncles often elongate, distally wingless; heads often nodding, usually borne singly or in leafy corymbiform arrays; involucres 20–70 mm diam Carduus nutans
1 Phyllary appendages 0.5–1.5 mm wide, usually narrower than appressed bases; peduncles short, if present, usually winged throughout or wingless only near tip; heads erect, 1–many, often clustered at branch tips; involucres 7–30 mm diam > 2
2 Involucres spheric or hemispheric > 3
2 Involucres cylindric or narrowly ellipsoid > 4
3 Corollas 13–20 mm; heads 18–25 mm; involucres 14–20 mm; abaxial leaf faces glabrate except for long, curled, septate hairs along veins Carduus acanthoides
3 Corollas 11–16 mm; heads 15–18 mm; involucres 12–17 mm; abaxial leaf faces sparsely to densely tomentose with fine, nonseptate hairs and often with curled, septate hairs along veins as well Carduus crispus
4 Heads 1–5 at ends of branches; phyllaries not scarious-margined, ± persistently tomentose, distally scabrous on margins and faces Carduus pycnocephalus
4 Heads 5–20 at ends of branches; phyllaries scarious-margined, glabrous or spar- ingly tomentose, distally ciliolate or glabrous Carduus tenuiflorus
... more about "Carduus"
David J. Keil +
Linnaeus +
Asteraceae tribe Cynareae +
Plumeless thistle +  and chardon +
Eurasia +  and Africa. +
From ancient name of thistlelike plant +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
batra1981a +, desrochers1988a +, desrochers1988b +, franco1976a +  and kazmi1964a +
Compositae +
Carduus +
Asteraceae tribe Cardueae +