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Nuttall's thistle

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

Phenology Flowering summer (Jun–Aug).
Habitat Roadsides, ditches, woodlands, usually in damp soil
Elevation 0–100 m (0–300 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA
[WildflowerSearch map]
[BONAP county map]
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
C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. engelmannii, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
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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