Cirsium nuttallii |
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Nuttall's thistle |
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Habit | Biennials, 20–350 cm; taprooted. |
Stems | usually single, erect, glabrous or villous with septate trichomes; branches few–many, ascending. |
Leaves | blades narrowly to broadly elliptic, (10–)15–60 × (2–)5–15 cm, thin, ± flexible, deeply pinnatifid, lobes narrow, spreading, coarsely dentate or lobed, main spines 2–5 mm, abaxial faces thinly tomentose but often wholly glabrate in age, adaxial glabrous or sparsely villous with septate trichomes; basal often absent at flowering, petioles slender, winged, bases tapered; principal cauline becoming sessile and gradually reduced distally, bases spiny-lobed, sometimes decurrent; distal reduced to linear bracts. |
Peduncles | 1–15 cm, essentially naked (not overtopped by crowded distal leaves). |
Involucres | hemispheric to campanulate, 1.5–2.5 × 1–2.5 cm, thinly arachnoid or glabrate. |
Corollas | white to pink, lavender, or purple, 17–25 mm, tubes 5–11 mm, throats 4–7 mm (noticeably wider than tubes), lobes 5–7 mm; style tips 3–4.5 mm. |
Phyllaries | in 6–10 series, strongly imbricate, green or brownish, ovate or elliptic (outer) to linear-lanceolate (inner), abaxial faces with narrow glutinous ridge; outer and middle appressed, bodies entire, spines abruptly spreading, slender, 1–2(–3) mm; apices of inner often flexuous, flat, attenuate. |
Heads | few–many, in open corymbiform or paniculiform arrays. |
Cypselae | dark brown, 3–4 mm, apical collars stramineous, 0.5 mm; pappi 17–21 mm (longer bristles shorter than corollas). |
2n | = 24, 26, 28. |
Cirsium nuttallii |
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Phenology | Flowering summer (Jun–Aug). |
Habitat | Roadsides, ditches, woodlands, usually in damp soil |
Elevation | 0–100 m (0–300 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; VA
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Discussion | Cirsium nuttallii occurs on the southern coastal plain from southeastern Virginia to southern Florida and west to eastern Louisiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 119. |
Parent taxa | Asteraceae > tribe Cardueae > Cirsium |
Sibling taxa | |
Synonyms | Carduus glaber, Carduus nuttallii |
Name authority | de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 651. (1838) |
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