The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

chardon de Flodman, Flodman's thistle, prairie thistle

gray thistle, wavy-leaf thistle, wavyleaf or gray or pasture thistle

Habit Perennials 30–140 cm; horizontal runner roots that produce root sprouts. Perennials, 20–230 cm; deeply seated runner roots that produce adventitious buds.
Stems

1–several, erect, gray- or white-tomentose;

branches 0–few, ascending.

1–several, erect or ascending, densely gray-tomentose;

branches 0–few, usually above middle, ascending.

Leaves

blades oblong-oblanceolate to narrowly elliptic, 4–40 × 1–10 cm, bases usually not decurrent, finely spiny-toothed and undivided to coarsely toothed or deeply pinnatifid, lobes broadly triangular to linear-lanceolate, often revolute-margined, main spines 1–7 mm, abaxial faces white-tomentose, adaxial faces green, thinly tomentose, ± glabrate;

basal usually absent or withered at flowering, winged petiolate;

principal cauline proximally winged-petiolate, distally sessile, well distributed, gradually reduced, bases usually not decurrent;

distal cauline well developed.

blades elliptic to oblong or ovate, 10–40 × 1–10 cm, margins strongly undulate, coarsely dentate or shallowly to deeply lobed, lobes ascending to spreading, ± triangular, well separated to closely spaced, spinulose and coarsely dentate or usually cleft into 2–3 lanceolate to triangular, often entire-margined, spine-tipped divisions, main spines (yellowish), 2–12+ mm, abaxial densely gray-tomentose, adaxial faces thinly tomentose;

basal sometimes present at flowering, winged-petiolate;

principal cauline becoming sessile and progressively reduced distally, widest at base, bases ± auriculate-clasping to short-decurrent;

distal reduced, spinier.

Peduncles

0–5 cm (elevated above distal leaves).

0–25+ cm.

Involucres

ovoid to broadly campanulate, 2–3.5 × 2.5–3.5 cm, thinly arachnoid.

ovoid to hemispheric or broadly campanulate, 2.5–4.5 × 1.5–4.5 cm, loosely arachnoid on phyllary margins or glabrate.

Corollas

purple (white), 23–36 mm, tubes 12–15 mm, throats 6–8.5 mm, lobes 5–9 mm;

style tips 4–7 mm.

lavender to pink, purple, or white, 24–50 mm, tubes 12–28 mm, throats 6–14 mm, lobes 6.5–13 mm;

style tips 5–7.5 mm.

Phyllaries

in 7–12 series, strongly imbricate, greenish with subapical darker central zone, ovate or lanceolate (outer) to linear (inner), abaxial faces with prominent glutinous ridge;

outer and middle entire, bodies appressed, entire, acute, spines abruptly spreading, slender, 2–4 mm;

apices of inner spreading, flexuous, narrow, flattened, finely serrulate, ± scabrous.

in 8–12 series, imbricate, ovate to lanceolate (outer) to linear-lanceolate (inner), abaxial faces with prominent glutinous ridge;

outer and middle appressed, spines spreading, 1.5–5 mm;

apices of inner narrow, often flexuous, flat, ± entire, spineless or weakly spiny.

Heads

erect, borne singly and terminal on main stem and branches, or few in corymbiform arrays from distal axils (not subtended by ring of spiny-margined bracts).

1–10+, terminal on branches, in leafy, ± corymbiform arrays.

Cypselae

light brown, 3–5 mm, apical collars stramineous, 0.5–1 mm;

pappi (white or tawny) 20–30 mm.

light to dark brown, 6–7 mm, bodies and apical collars concolorous, narrow;

pappi 20–38 mm (usually scabridulous).

2n

= 22, 24.

= 26.

Cirsium flodmanii

Cirsium undulatum

Phenology Flowering summer (Jun–Sep). Flowering spring–autumn (May–Oct).
Habitat Tallgrass, mixedgrass, shortgrass prairies, meadows, pastures, often in damp soil Mixedgrass prairie, shortgrass prairie, Palouse prairie, sagebrush deserts, pinyon-juniper woodlands, openings in montane coniferous forests, often in disturbed areas
Elevation 100–2400 m (300–7900 ft) 100–2800 m (300–9200 ft)
Distribution
from FNA
CO; IA; IL; KS; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; ON; QC; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; GA; IA; ID; IL; IN; KS; MI; MN; MO; MT; ND; NE; NM; OK; OR; PA; SD; TX; UT; WA; WI; WY; AB; BC; MB; SK; Mexico (Chihuahua, Coahuila, Durango, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Cirsium flodmanii ranges from Saskatchewan and Alberta south through the northern Great Plains and intermountain valleys of Montana and Wyoming to northeastern Colorado and east through the prairies to Minnesota and Iowa, and in widely scattered locations eastward to northern Illinois, southern Wisconsin, southern Ontario, and southern Quebec. It is known to hybridize with C. muticum and C. undulatum. Hybrids between C. flodmanii and C. undulatum are highly sterile with numerous meiotic irregularities (S. Dabydeen 1987).

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

Cirsium undulatum is widely distributed in the wstern half of North America from the dry plains and plateaus of the Pacific Northwest eastward across the Great Plains to Manitoba and the Dakotas and south to Texas, New Mexico, and northwestern Mexico. It occurs in scattered localities in the Rocky Mountains and northeastern Great Basin region. At least some of the few widely scattered records from the eastern United States are probably introductions. Cirsium undulatum is both widespread and variable. Plants of the Great Plains region tend to be low-growing with a few large heads and elongate corollas. Plants of the Pacific Northwest are usually taller and produce smaller, more numerous heads with shorter corollas. A detailed study of this species might reveal races worthy of recognition as infraspecific taxa.

Wavyleaf thistle is listed by California as a noxious weed. However, most reports of Cirsium undulatum in California are based upon misidentifications of C. canescens. Cirsium undulatum is known to hybridize with C. flodmanii, C. hookerianum, and C. scariosum var. coloradense. J. T. Howell (1960b) reported that C. undulatum was suspected to hybridize with C. brevifolium in the Pacific Northwest.

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

Source FNA vol. 19, p. 120. FNA vol. 19, p. 120.
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. 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. 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. 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. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
Synonyms Carduus flodmanii, C. oblanceolatum Carduus undulatus, C. megacephalum, C. undulatum var. megacephalum
Name authority (Rydberg) Arthur: Torreya 12: 34. (1912) (Nuttall) Sprengel: Syst. Veg. 3: 374. (1826)
Web links