Cirsium remotifolium

(Hooker) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle

in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 655. 1838.

Common names: Remote-leaved or fewleaf thistle
IllustratedEndemic
Basionym: Carduus remotifolius Hooker Fl. Bor.-Amer. 1: 302. 1833
Treatment appears in FNA Volume 19. Treatment on page 129. Mentioned on page 103, 105, 107, 128, 130, 1.

Perennials, 20–150 cm, monocarpic; taprooted or polycarpic, perennating by runner roots. 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. 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. 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. Peduncles (0–) 2–15 cm. Involucres ovoid to hemispheric or campanulate, 1.5–2.5 × 1.5–3.5 cm, glabrous to arachnoid-floccose. 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. 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. Cypselae tan to dark-brown, 4.5–5.5 mm, apical collars differentiated or not; pappi 13–23 mm. 2n = 32.

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.

Selected References

None.

Key

1 Phyllary margins ciliate with tiny spreading to recurved spines Cirsium remotifolium 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 Cirsium remotifolium var. remotifolium
2 Phyllaries oblong to obovate, often strongly graduated, most or all with dilated, scarious, erose to lacerate-dentate margins Cirsium remotifolium var. odontolepis

"fine" is not a number.

... more about "Cirsium remotifolium"
green +  and gray +
villous +, glabrate +  and arachnoid-tomentose +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
not +  and differentiated +
paniculiform +, racemiform +  and corymbiform +
indeterminate +  and determinate +
David J. Keil +
(Hooker) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle +
winged-petiolate +  and sessile +
lacerate-dentate +  and entire +
auriculate-clasping +
auriculate +  and narrowed +
expanded +
Carduus remotifolius +
compound +  and simple +
7 cm70 mm <br />0.07 m <br /> (30 cm300 mm <br />0.3 m <br />) +
dentate or;shallowly deeply pinnatifid +
1cm;15cm +
10-nerved or 20-nerved +  and rugose +
ascending;arising +
slender +
tawny +  and white +
Remote-leaved or fewleaf thistle +
actinomorphic +
creamy white +  and purple +
1.8 cm18 mm <br />0.018 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
tan +  and dark-brown +
compressed +  and ovoid +
fertile +  and bisexual +
sometimes spinier +
less deeply divided +, unlobed +  and bractlike +
Calif. +, Oreg. +  and Wash. +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
indeterminate +
each +  and sessile +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
glabrous +  and arachnoid-floccose +
ovoid;hemispheric or campanulate +
1.5 cm15 mm <br />0.015 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
linear +  and triangular-ovate dentate +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
lacerate-dentate +, entire +  and spinulose-dentate +
usually lobed +  and dissected +
2-carpellate +
persistent +
1.3 cm13 mm <br />0.013 m <br /> (2.3 cm23 mm <br />0.023 m <br />) +
0 cm0 mm <br />0 m <br /> (2 cm20 mm <br />0.02 m <br />) +
2 cm20 mm <br />0.02 m <br /> (15 cm150 mm <br />0.15 m <br />) +
middle +  and outer +
papillate +  and smooth +
sessile +  and winged-petiolate +
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
inconspicuous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
Illustrated +  and Endemic +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
spiny-winged +, simple +  and branched +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Compositae +
Cirsium remotifolium +
species +
cylindric +
expanded +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
bristly-dentate to coarsely +
slender +
0.7 cm7 mm <br />0.007 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
20 cm200 mm <br />0.2 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
tree +, vine +, shrub +  and subshrub +