Cirsium undulatum

(Nuttall) Sprengel

Syst. Veg. 3: 374. 1826.

Common names: Wavyleaf or gray or pasture thistle
Basionym: Carduus undulatus Nuttall Gen. N. Amer. Pl. 2: 130. 1818
Synonyms: Cirsium megacephalum (A. Gray) Cockerell ex Daniels Cirsium undulatum var. megacephalum (A. Gray) Fernald
Treatment appears in FNA Volume 19. Treatment on page 120. Mentioned on page 100, 101, 106, 107, 119, 121, 122, 149.

Perennials, 20–230 cm; deeply seated runner roots that produce adventitious-buds. Stems 1–several, erect or ascending, densely gray-tomentose; branches 0–few, usually above middle, ascending. Leaves: 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. Heads 1–10+, terminal on branches, in leafy, ± corymbiform arrays. Peduncles 0–25+ cm. Involucres ovoid to hemispheric or broadly campanulate, 2.5–4.5 × 1.5–4.5 cm, loosely arachnoid on phyllary margins or glabrate. Phyllaries 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. Corollas 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. Cypselae light to dark-brown, 6–7 mm, bodies and apical collars concolorous, narrow; pappi 20–38 mm (usually scabridulous). 2n = 26.


Phenology: Flowering spring–autumn (May–Oct).
Habitat: Mixedgrass prairie, shortgrass prairie, Palouse prairie, sagebrush deserts, pinyon-juniper woodlands, openings in montane coniferous forests, often in disturbed areas
Elevation: 100–2800 m

Distribution

V19-75-distribution-map.gif

Alta., B.C., Man., Sask., Ariz., Calif., Colo., Ga., Idaho, Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Dak., Okla., Oreg., Pa., S.Dak., Tex., Utah, Wash., Wis., Wyo., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (Sonora)

Discussion

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.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Cirsium undulatum"
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
corymbiform +, paniculiform +, subcapitate +, spiciform +  and racemiform +
indeterminate +  and determinate +
David J. Keil +
(Nuttall) Sprengel +
winged-petiolate +
less auriculate-clasping +  and short-decurrent +
decurrent +
Carduus undulatus +
compound +  and simple +
10 cm100 mm <br />0.1 m <br /> (40 cm400 mm <br />0.4 m <br />) +
elliptic;oblong or ovate +
1cm;10cm +
concolorous +
10-nerved or 20-nerved +  and rugose +
tawny +  and white +
Wavyleaf or gray or pasture thistle +
actinomorphic +
lavender +  and pink purple or white +
2.4 cm24 mm <br />0.024 m <br /> (5 cm50 mm <br />0.05 m <br />) +
light +  and dark-brown +
compressed +  and ovoid +
fertile +  and bisexual +
Alta. +, B.C. +, Man. +, Sask. +, Ariz. +, Calif. +, Colo. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Mich. +, Minn. +, Mo. +, Mont. +, Nebr. +, N.Mex. +, N.Dak. +, Okla. +, Oreg. +, Pa. +, S.Dak. +, Tex. +, Utah +, Wash. +, Wis. +, Wyo. +, Mexico (Chihuahua) +, Mexico (Coahuila) +, Mexico (Durango) +  and Mexico (Sonora) +
100–2800 m +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Mixedgrass prairie, shortgrass prairie, Palouse prairie, sagebrush deserts, pinyon-juniper woodlands, openings in montane coniferous forests, often in disturbed areas +
indeterminate +
each +  and sessile +
2.5 cm25 mm <br />0.025 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
glabrate +  and arachnoid +
ovoid;hemispheric or broadly campanulate +
1.5 cm15 mm <br />0.015 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
entire-margined +
cleft +, dentate +  and spinulose +
ascending;spreading +
lanceolate +  and triangular +
0.2 cm2 mm <br />0.002 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
entire +  and dentate +
coarsely dentate or +  and shallowly deeply lobed +
spiny +, spineless +  and entire +
2-carpellate +
persistent +
2 cm20 mm <br />0.02 m <br /> (3.8 cm38 mm <br />0.038 m <br />) +
0 cm0 mm <br />0 m <br /> (25 cm250 mm <br />0.25 m <br />) +
Flowering spring–autumn (May–Oct). +
middle +  and outer +
weakly to strongly +
papillate +  and smooth +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
spiny-winged +, simple +  and branched +
ascending +  and erect +
1 +  and several +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.5 cm5 mm <br />0.005 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
Cirsium megacephalum +  and Cirsium undulatum var. megacephalum +
Cirsium undulatum +
species +
cylindric +
expanded +
0.6 cm6 mm <br />0.006 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
bristly-dentate to coarsely +
slender +
1.2 cm12 mm <br />0.012 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
20 cm200 mm <br />0.2 m <br /> (230 cm2,300 mm <br />2.3 m <br />) +
tree +, vine +, shrub +  and subshrub +