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Anderson's thistle, rose thistle

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

Habit Perennials (but often appearing biennial), (15–)40–70(–100) cm; rootstocks producing erect, taprooted caudices and rosettes. Perennials, 20–230 cm; deeply seated runner roots that produce adventitious buds.
Stems

usually 1, erect, subglabrous to puberulent and/or tomentose;

branches 0–several, stiffly ascending.

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

branches 0–few, usually above middle, ascending.

Leaves

blades ± elliptic, 8–35 × 4–8 cm, divided about halfway to midveins, lobes spreading, triangular, coarsely dentate or with a few broad lobes, obtuse to acute, main spines 1–5 mm, abaxial faces green or gray, thinly tomentose, adaxial green and glabrous to sparingly pilose;

basal often present at flowering, spiny winged-petiolate;

main cauline reduced distally, bases clasping;

distal much reduced, linear-oblong, usually less deeply lobed and often spinier than proximal.

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

0–20 cm.

0–25+ cm.

Involucres

broadly cylindric to narrowly campanulate, 3–5 × 2–4 cm, loosely arachnoid or ± glabrous, finely short-ciliate.

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

Corollas

red to reddish purple, 30–45 mm, tubes 10–20 mm, throats 10–16 mm, lobes 9–11 mm;

style tips 3.5–5 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 6–8 series, imbricate, outer green, inner purple to red, linear-lanceolate (outer) to linear (inner), abaxial faces without glutinous ridge;

outer and mid bodies short, appressed, entire or spinulose-ciliate, apices long-spreading to ascending, entire or spinulose-ciliate or rarely with expanded, fringed appendages, spines straight, weak, 1–3 mm;

apices of inner red to purple, straight or rarely twisted, long, flat, entire.

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

1–6, borne singly or in corymbiform, racemiform, or spiciform arrays.

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

Cypselae

brown, 6–7 mm, apical collars narrow;

pappi 25–40 mm.

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

pappi 20–38 mm (usually scabridulous).

2n

= 32, 64.

= 26.

Cirsium andersonii

Cirsium undulatum

Phenology Flowering summer (Jul–Sep). Flowering spring–autumn (May–Oct).
Habitat Moist to dry soils, openings in montane woodlands, montaine coniferous forests, aspen groves Mixedgrass prairie, shortgrass prairie, Palouse prairie, sagebrush deserts, pinyon-juniper woodlands, openings in montane coniferous forests, often in disturbed areas
Elevation 1100–2900 m (3600–9500 ft) 100–2800 m (300–9200 ft)
Distribution
from FNA
CA; ID; NV
[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 andersonii grows in the Cascade Range of northern California south through the Sierra Nevada of eastern California and western Nevada. It has been reported from the mountains of southwestern Idaho, but I have not seen specimens from there.

Heads of Cirsium andersonii are actively visited by hummingbirds as well as a variety of insects (P. L. Barlow-Irick 2002).

(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. 145. FNA vol. 19, p. 120.
Parent taxa Asteraceae > tribe Cardueae > Cirsium Asteraceae > tribe Cardueae > Cirsium
Sibling taxa
C. altissimum, 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. 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 Cnicus andersonii Carduus undulatus, C. megacephalum, C. undulatum var. megacephalum
Name authority (A. Gray) Petrak: Bot. Tiddsskr. 31: 68. (1911) (Nuttall) Sprengel: Syst. Veg. 3: 374. (1826)
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