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bull or common or spear thistle, bull thistle, chardon vulgaire ou lancéolé, common thistle, gros chardon, piqueux, spear thistle

dune thistle, Pitcher's thistle, sand-dune thistle

Habit Biennials, 30–200(–300) cm; taproots. Biennials or short-lived monocarpic perennials, 20–100 cm; taproots long.
Stems

1–many, erect or ascending, branches few–many, ascending, villous with septate trichomes.

1 or few, erect, densely gray-tomentose;

branches 0 to several, ascending to spreading.

Leaves

blades oblong-lanceolate to obovate, 15–40 × 6–15 cm, margins plane or revolute, coarsely 1–2-pinnatifid with rigidly divergent lobes, sometimes merely spinose-dentate, lobes triangular to lanceolate, entire to spiny-dentate, main spines 2–10 mm, abaxial faces gray-tomentose, villous with septate trichomes along veins, adaxial green, covered with short appressed bristlelike spines, sometimes tomentose when young;

basal present or absent at flowering, petioles winged, bases tapered;

principal cauline winged-petiolate, mid and distal becoming sessile, well distributed or not, progressively reduced distally, at least distal decurrent as long spiny wings;

distal cauline often more deeply lobed than proximal, main lobes rigidly spiny, margins spinulose, otherwise entire.

blades elliptic to obovate, 10–30 × 8–14 cm, deeply divided nearly to midveins, lobes ascending to spreading, linear, remote, margins revolute, entire or minutely spinulose, main spines 1–2 mm, faces gray-tomentose, more densely so abaxially;

basal present or withered at flowering, petiolate;

principal cauline well distributed, bases decurrent as linear-lobed to spiny wings 1–3 cm;

distal cauline well developed.

Peduncles

1–6 cm.

0–5 cm.

Involucres

hemispheric to campanulate, 3–4 × 2–4 cm, loosely arachnoid-tomentose.

ovoid to campanulate, 2–3 × 2–3 cm, loosely arachnoid on phyllary margins or glabrate.

Corollas

purple (rarely white), 25–35 mm, tubes 18–25 mm, throats 5–6 mm, lobes 5–7 mm;

style tips 3.5–6 mm.

dull white or pinkish-tinged (rarely rich purple), 20–30 mm, tubes 8.5–15 mm, throats 4.5–10 mm, lobes 3–8 mm;

style tips 3.5–5.5 mm.

Phyllaries

in 10–12 series, strongly imbricate, linear-lanceolate (outer) to linear (inner), outer and middle appressed, (bases stramineous), margins entire, abaxial faces without glutinous ridge, apices radiating, greenish, spines 2–5 mm;

apices of inner phyllaries flat, serrulate to minutely erose.

in 6–8 series, imbricate, ovate-lanceolate (outer) to linear-lanceolate (inner), abaxial faces with narrow glutinous ridge;

outer and middle appressed, acute, spines ascending to spreading, slender, 1–2(–3) mm;

apices of inner often flexuous, flattened, spineless, scabrid.

Heads

few–many in corymbiform or paniculiform arrays.

1–20+ in corymbiform arrays.

Cypselae

light brown with darker streaks, 3–4.5 mm, apical collar not differentiated;

pappi 20–30 mm.

light brown, sometimes with darker streaks, 6–7.5 mm, apical collars lighter colored, very narrow;

pappi 15–30 mm, usually noticeably shorter than corolla.

2n

= 68.

= 34.

Cirsium vulgare

Cirsium pitcheri

Phenology Flowering mostly summer (Jun–Sep), year round in areas with mild climates. Flowering spring–summer (May–Sep).
Habitat Invasive weed of disturbed sites, pastures, meadows, forest openings, roadsides Sand dunes and beaches
Elevation 0–2200 m (0–7200 ft) 180–200 m (600–700 ft)
Distribution
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; SPM; Eurasia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
IL; IN; MI; WI; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Native to Eurasia, Cirsium vulgare is the only thistle in North America with bristlelike spines borne on the adaxial leaf faces. These structures are variously described in the literature as trichomes (“spreading hirsute,” “scabrous-hispid,” “coarsely hispid,” “rigid, rather pungent setae,” “prickly-hairy”), prickles, or spines (“setose-spinulose,” “appressed and dense spines”). My examination of cleared leaves of C. vulgare indicated that these structures are not epidermal outgrowths (trichomes or prickles) but emerge from fine veinlets within the tissues of the leaf. As such, they are properly treated as spines.

Bull thistle is a noxious weed that has invaded disturbed habitats across the continent. Distasteful to livestock, it can increase in heavily grazed pastures. It occurs in a wide variety of habitats.

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

Cirsium pitcheri is endemic to beach and dune habitats around lakes Huron, Michigan, and Superior. It has been extirpated from portions of its former range at the southern end of Lake Michigan. It is threatened by foot traffic, off-road vehicular activity, and clearing and development of beachside habitats. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

Source FNA vol. 19, p. 109. FNA vol. 19, p. 122.
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. 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. 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. 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. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. perplexans, 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 vulgaris, Carduus lanceolatus Cnicus pitcheri
Name authority (Savi) Tenore: Fl. Napol. 5: 209. (1835) (Torrey ex Eaton) Torrey & A. Gray: Fl. N. Amer. 2: 456. (1843)
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