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

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

Eaton's thistle, mountaintop thistle, Peck's thistle, Steens Mountain thistle

Habit Perennials, 20–150 cm, monocarpic; taprooted or polycarpic, perennating by runner roots. Perennials, 10–150 cm; taprooted caudices.
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, (fleshy), erect or ascending, simple to sparingly branched in distal 1/2, sometimes openly branched, glabrous to villous or tomentose with septate trichomes, sometimes ± glabrate;

branches on distal stems 0–many, ascending.

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 oblong, 10–30 × 1–5 cm, margins usually strongly undulate, unlobed and spiny-dentate or shallowly to deeply pinnatifid with 10–20 pairs of lobes, teeth or lobes closely spaced, often overlapping, lance-oblong to broadly triangular, deeply 3-lobed, ± spiny-dentate, main spines 2–12 mm, abaxial faces glabrous or villous with septate trichomes along midveins to densely arachnoid-tomentose, adaxial glabrous or villous with septate trichomes along midveins;

basal often present at flowering, spiny winged-petiolate or sessile;

principal cauline many, well distributed, proximally ± winged-petiolate, distally sessile, gradually reduced;

distal not much reduced, often closely subtending heads.

Peduncles

(0–)2–15 cm.

0–14+ cm.

Involucres

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

green or suffused with dark purple, broadly ovoid to campanulate, 2–5 × 1.5–5 cm (appearing wider when pressed), loosely to densely villous or tomentose with septate trichomes and/or arachnoid-tomentose with finer, non-septate trichomes.

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.

ochroleucous or yellow to lavender, pink, or purple, 15–35 mm, tubes 3.5–10 mm, throats 5–14 mm, lobes (linear), 4–12.5 mm;

style tips 3–6 mm, conspicuously exserted beyond corolla lobes.

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 4–5 series, subequal, bases short-appressed, abaxial faces without or with very narrow glutinous ridge, apices usually stiffly ascending to spreading, linear-acicular, tapering to spines 7–35 mm;

outer usually pinnately spiny, sometimes entire;

apices of inner straight, plane or spine-tipped.

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–many, erect or nodding, closely subtended by spiny-fringed bracts, usually sessile or short-pedunculate and crowded in subcapitate, spiciform, or racemiform (less commonly in openly branched) arrays.

Cypselae

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

pappi 13–23 mm.

dark brown, 5.5–7 mm, apical collars stramineous or not differentiated;

pappi 12–25 mm.

2n

= 32.

Cirsium remotifolium

Cirsium eatonii

Distribution
from FNA
CA; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; ID; MT; NM; NV; OR; UT; WY; Rocky Mountains and high peaks of Great Basin desert region
[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 7 (7 in the flora).

Cirsium eatonii is a polymorphic species widely distributed in a high elevation archipelago across the central Rocky Mountains and the Intermountain Region. During Pleistocene glacial episodes, the progenitors of this species complex undoubtedly occupied lower elevation sites and likely had more contiguous populations. Post-glacial isolation of these populations in allopatric high elevation sites has allowed them to differentiate to a greater or lesser extent. Prehistoric or recent introgressive hybridization with other thistle species probably has contributed to the diversification of the complex (R. J. Moore and C. Frankton 1965). Several of the races recognized here as varieties have been treated in the past as species (e.g., C. clokeyi, C. peckii). Their current geographic isolation and more or less distinctive features might support such recognition, but application of this approach across the complex would result in a proliferation of microspecies.

(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. Involucres densely tomentose, individual phyllaries ± obscured by pubescence
→ 2
1. Involucres glabrous or thinly tomentose, individual phyllaries evident
→ 5
2. Arrays nodding; corollas yellow or pink to pale purple
var. eriocephalum
2. Arrays erect; corollas white or pink to deep purple
→ 3
3. Corolla throats 8–11.5 mm; se Oregon, nw Nevada
var. peckii
3. Corolla throats 3.5–8 mm
→ 4
4. Plants 50–150 cm, strictly erect; corollas pink or pale to deep purple; s Colorado
var. hesperium
4. Plants 10–65 cm, ascending to erect; corollas white to pink or lavender; Idaho and Montana to Utah and n Colorado
var. murdockii
5. Corollas usually 25–35 mm
→ 6
5. Corollas usually 17–25 mm
→ 7
6. Longest pappus bristles 16–18 mm
var. clokeyi
6. Longest pappus bristles 20–25 mm
var. viperinum
7. Most outer phyllaries with lateral spines; Nevada and Utah
var. eatonii
7. Most outer phyllaries without lateral spines; nw Nevada and se Oregon
var. peckii
Source FNA vol. 19, p. 129. FNA vol. 19.
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. 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
Subordinate taxa
C. remotifolium var. odontolepis, C. remotifolium var. remotifolium, C. remotifolium var. rivulare
C. eatonii var. clokeyi, C. eatonii var. eatonii, C. eatonii var. eriocephalum, C. eatonii var. hesperium, C. eatonii var. murdockii, C. eatonii var. peckii, C. eatonii var. viperinum
Synonyms Carduus remotifolius Cnicus eatonii
Name authority (Hooker) de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 655. (1838) (A. Gray) B. L. Robinson: Rhodora 13: 240. (1911)
Web links