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Nuttall's thistle

fountain thistle

Habit Biennials, 20–350 cm; taprooted.
Stems

usually single, erect, glabrous or villous with septate trichomes;

branches few–many, ascending.

1–several, erect, loosely arachnoid-tomentose, glandular-pilose;

branches several to many, spreading.

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.

blades oblanceolate to oblong or elliptic, 20–70 × 5–16 cm, strongly undulate, shallowly to deeply pinnatifid, lobes coarsely toothed or with triangular secondary lobes, main spines 3–15 mm, abaxial faces more densely tomentose, adaxial densely glandular with short, multicellular trichomes and ± tomentose with fine, arachnoid, non-septate trichomes;

basal often present at flowering, petiolate;

principal cauline well distributed, becoming sessile, gradually reduced distally, bases auriculate-decurrent with broad, spiny-margined wings 3 cm or less;

distal cauline leaves progressively reduced, ± bractlike.

Peduncles

1–15 cm, essentially naked (not overtopped by crowded distal leaves).

0–7 cm.

Involucres

hemispheric to campanulate, 1.5–2.5 × 1–2.5 cm, thinly arachnoid or glabrate.

(green to purple), hemispheric or campanulate, 1.5–3 × 2–5 cm, glabrous or puberulent.

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.

white to pinkish or lavender, 14.5–22 mm, tubes 5–8 mm, throats 4.5–9 mm, lobes 3–8 mm;

style tips 2.5–4.5 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.

in 6–10 series, imbricate, ovate to lanceolate, abaxial faces without glutinous ridge;

outer and mid bases appressed, short, bodies entire to erose or ciliolate (rarely outer spine-margined), apices spreading to recurved or reflexed, long, dilated, adaxially puberulent, spines 1–6 mm;

apices of inner erect or reflexed, flattened or tipped with short spines.

Heads

few–many, in open corymbiform or paniculiform arrays.

few–many, ± nodding, in paniculiform or corymbiform arrays, bracts leafy or much reduced.

Cypselae

dark brown, 3–4 mm, apical collars stramineous, 0.5 mm;

pappi 17–21 mm (longer bristles shorter than corollas).

brownish, 3.4–5 mm, apical collars tan;

pappi 12–15 mm.

Monocarpic

perennials, 50–220 cm; woody tap-rooted caudices with numerous coarse, fibrous lateral roots, sometimes forming new rosettes from root sprouts.

2n

= 24, 26, 28.

Cirsium nuttallii

Cirsium fontinale

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]
from USDA
c Calif
[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.)

Varieties 3 (3 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Cypselae 4.1–5 mm; phyllary spines 1–2 mm
var. fontinale
1. Cypselae 3.4–4.1 mm; phyllary spines 2–6 mm
→ 2
2. Longer spines of cauline leaves 10–18 mm; most phyllaries without marginal spines
var. campylon
2. Longer spines of cauline leaves 4–7 mm; many outer phyllaries with marginal spines
var. obispoense
Source FNA vol. 19, p. 119. FNA vol. 19, p. 161.
Parent taxa Asteraceae > tribe Cardueae > Cirsium 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
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. 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. nuttallii, 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
Subordinate taxa
C. fontinale var. campylon, C. fontinale var. fontinale, C. fontinale var. obispoense
Synonyms Carduus glaber, Carduus nuttallii Cnicus fontinalis
Name authority de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 651. (1838) (Greene) Jepson: Fl. W. Calif., 505. (1901)
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