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few-leaf thistle, mountain thistle, Pacific fringe thistle, remote-leaf thistle, weak thistle

bristly or horrid or yellow or bull thistle, bristly thistle, bull thistle, horrid thistle, yellow thistle

Habit Perennials, 20–150 cm, monocarpic; taprooted or polycarpic, perennating by runner roots. Biennials or perennials, (± fleshy), 15–250 cm; stout taproots and a fascicle of fleshy lateral roots, often perennating by root sprouts.
Stems

usually 1, erect, finely arachnoid-tomentose, sometimes villous with septate trichomes below nodes;

branches 0–10+, slender, usually arising in distal 1/2, ascending.

1–several, usually erect, often stout, glabrous to densely tomentose;

branches 0–many, spreading to ascending, short, stout.

Leaves

blades linear-oblong to oblanceolate or elliptic, 7–30 × 1–15 cm, unlobed and spinulose to dentate or shallowly to deeply pinnatifid, lobes well separated, linear to triangular-ovate, dentate to deeply lobed, main spines 2–5 mm, slender, abaxial faces green to gray, thinly to densely arachnoid-tomentose, sometimes glabrate, sometimes villous with septate trichomes along veins, adaxial green, glabrous;

basal sometimes present at flowering, sessile or winged-petiolate;

principal cauline mostly in proximal 1/2, winged-petiolate or sessile, bases narrowed, sometimes auriculate;

distal well separated, progressively reduced, becoming bractlike, often unlobed or less deeply divided than the proximal, sometimes spinier than proximal, bases often distally expanded and auriculate-clasping.

blades linear to oblanceolate or oblong-elliptic, 10–40 × 2–10 cm, unlobed and spiny-dentate to deeply pinnatifid, lobes spiny-dentate or coarsely lobed, main spines stout, 5–30 mm, abaxial faces subglabrous to loosely tomentose, adaxial glabrous to ± densely villous with septate trichomes;

basal present at flowering, spiny winged-petiolate, bases often tapered;

principal cauline sessile, well distributed, often not much reduced distally, bases often ± auriculate-clasping;

distal cauline often spinier than the proximal.

Peduncles

(0–)2–15 cm.

0–5 cm.

Involucres

ovoid to hemispheric or campanulate, 1.5–2.5 × 1.5–3.5 cm, glabrous to arachnoid-floccose.

hemispheric to campanulate, 3–5 × 3–8 cm.

Corollas

creamy white to purple, 18–28 mm, tubes 7–12 mm, throats 5–12 mm, lobes 3.5–7 mm, style tips 4–6 mm.

white to yellow, pink, purple, or red, 30–47 mm, tubes 11–30 mm, throats 6–10 mm, lobes 7–10 mm;

style tips 3–5 mm.

Phyllaries

in 6–8 series, subequal to strongly imbricate, green, linear to obovate (outer) to linear (inner), abaxial faces with inconspicuous glutinous ridge;

outer and middle bases appressed, margins entire to spinulose-dentate or broad, scarious, lacerate-dentate, spines absent or ascending to spreading, 1–2 mm;

apices of inner sometimes flexuous or reflexed, narrow, flat, entire or expanded, scarious, and lacerate-dentate.

in 5–9 series, subequal to imbricate, light green to stramineous, lanceolate to linear, distally often with reddish margins, abaxial faces without glutinous ridge, often ± thinly tomentose, often scabridulous in submarginal bands;

outer and middle appressed-ascending, bodies usually reddish-tinged, margins setulose-ciliolate, apices acuminate, spines 1–2 mm, weak;

apices of inner straight, flat.

Heads

few–many, borne singly or in openly branched in corymbiform, racemiform, or paniculiform arrays on main stem and branches, sometimes also in distal axils, not closely subtended by clustered leaf bracts.

1–20 in subcapitate to corymbiform arrays (each closely subtended by an involucre-like ring of spiny-margined bracts).

Cypselae

tan to dark brown, 4.5–5.5 mm, apical collars differentiated or not;

pappi 13–23 mm.

straw-colored to tan, 4–6 mm, apical collars weakly differentiated;

pappi 25–35 mm.

2n

= 32.

= 32, 33, 34, 35.

Cirsium remotifolium

Cirsium horridulum

Distribution
from FNA
CA; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; DE; FL; GA; LA; MA; MD; ME; MS; NC; NH; NJ; NY; OK; PA; RI; SC; TN; TX; VA; Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

Cirsium remotifolium occurs from the Coast Ranges and valleys of the Pacific Northwest to the western slopes of the Cascade and Klamath ranges, south in the California North Coast Ranges to the San Francisco Bay region. It is closely related to the C. clavatum complex of the Rocky Mountains region. Both have a similar growth habit and some forms variably express the character of broadly scarious, lacerate-toothed phyllary margins. Gray, in naming Cnicus carlinoides var. americanus, included as syntypes both California and Colorado specimens. F. Petrak (1917) treated both the West Coast plants and those of the Rocky Mountains as Cirsium subsect. Americana, recognizing C. remotifolium with several infraspecific taxa plus two other species, C. callilepis and C. amblylepis from the West Coast, and four additional species from the Rocky Mountains. A. Cronquist (1955) rejected Petrak’s subspecies, treating C. remotifolium in a restricted sense, limited to plants of Washington and Oregon without dilated phyllary tips, and circumscribed C. centaureae broadly to include the Rocky Mountains and West Coast plants with dilated phyllary tips. Because of the frequent presence of dilated phyllary tips in C. remotifolium in the restricted sense, Cronquist acknowledged the likelihood of past introgression with C. centaureae in the broad sense.

J. T. Howell (1960b) recognized three species: Cirsium remotifolium, C. acanthodontum, and C. callilepis, the latter with four varieties collectively corresponding to the West Coast representatives of C. centaureae (in the sense of Cronquist). Because of the great similarity of the various West Coast plants and their intergradation, I see no value in recognizing two or more species.

The West Coast and Rocky Mountains plants are clearly related, but are separated by the Great Basin region and there is little chance of current genetic interchange. As is often the case with American Cirsium, genetic enrichment from past hybridization with other nearby species within their respective areas has likely been fertile ground for evolutionary diversification. Different species have contributed genes in the Pacific states and in the Rockies. I have chosen to recognize two geographically-based species complexes, each with intergrading races here treated as varieties. I treat the West Coast plants as C. remotifolium and the Rocky Mountains plants as C. clavatum.

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

Varieties 4 (3 in the flora).

Although several variants have been given taxonomic recognition as species, these seem at most races. Flower color varies greatly, sometimes within populations and sometimes on a populational or regional basis. Herbarium specimens are sometimes difficult to assign to variety.

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

Key
1. Phyllary margins ciliate with tiny spreading to recurved spines
var. rivulare
1. Phyllary margins unappendaged or dilated, scarious, and ± lacerate-toothed
→ 2
2. Phyllaries narrowly oblong or linear, often ± subequal, all or most without scarious-dilated margins
var. remotifolium
2. Phyllaries oblong to obovate, often strongly graduated, most or all with dilated, scarious, erose to lacerate-dentate margins
var. odontolepis
1. Stems densely tomentose; involucres ± densely tomentose
var. horridulum
1. Stems glabrous or sparsely tomentose; involucres glabrous
→ 2
2. Leaves shallowly to deeply pinnatifid, main spines 10–30 mm
var. megacanthum
2. Leaves spinose-dentate to shallowly pinnatifid, main spines mostly 5–10 mm
var. vittatum
Source FNA vol. 19, p. 129. FNA vol. 19, p. 114.
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. 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. 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. remotifolium var. odontolepis, C. remotifolium var. remotifolium, C. remotifolium var. rivulare
C. horridulum var. horridulum, C. horridulum var. megacanthum, C. horridulum var. vittatum
Synonyms Carduus remotifolius
Name authority (Hooker) de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 655. (1838) Michaux: Fl. Bor.-Amer. 2: 90. (1803)
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