Cirsium remotifolium
Cirsium edule
few-leaf thistle, mountain thistle, Pacific fringe thistle, remote-leaf thistle, weak thistle
cardon, edible thistle
usually 1, erect, finely arachnoid-tomentose, sometimes villous with septate trichomes below nodes;
branches 0–10+, slender, usually arising in distal 1/2, ascending.
usually 1, erect, simple to openly branched in distal 1/2, ± villous with jointed trichomes, sometimes finely arachnoid, sometimes ± glabrate;
branches 0–many, ascending.
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 to elliptic or oblanceolate, 5–50 × 1–10 cm, plane to moderately undulate, coarsely dentate to deeply pinnatifid, lobes 5–10 well separated, linear, narrowly to broadly triangular, spinulose to spiny-dentate or shallowly lobed, main spines 3–10 mm, abaxial faces thinly to densely villous along major veins with septate trichomes, sometimes thinly arachnoid-tomentose, sometimes glabrescent, adaxial glabrous to sparsely villous or shaggy-tomentose along midveins with septate trichomes;
basal often absent at flowering, spiny winged-petiolate or sessile;
principal cauline well distributed, only gradually reduced, bases auriculate-clasping;
distal moderately to strongly reduced, thin, often spinier than the proximal.
(0–)2–15 cm.
0–5(–30) cm.
ovoid to hemispheric or campanulate, 1.5–2.5 × 1.5–3.5 cm, glabrous to arachnoid-floccose.
narrowly ovoid to hemispheric or campanulate, 1.5–3.5 × 1.5–4 cm (including spines), loosely to densely arachnoid with fine, non-septate trichomes.
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.
purple (pink or white), (15–)18–22(–33) mm, tubes 7–11 mm, throats (4–)5–8.5(–13) mm, lobes linear but not filiform, not knobbed at tips, (2–)4.5–7(–10) mm;
style tips 3–4(–5) mm, conspicuously exserted beyond corolla lobes.
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 4–8 series, subequal, green or often purplish, bodies short, appressed, abaxial faces without glutinous ridge, apices stiffly radiating to ascending, straight or flexuous, narrowly linear, plane to acicular, spines straight, slender, 1–10+ mm;
outermost spiny-fringed or entire, mid entire or minutely serrulate;
apices of inner straight, sometimes expanded and erose, flat.
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, often crowded and ± sessile in tight clusters at stem tips, closely subtended by clusters of leafy bracts or not, collectively forming corymbiform or paniculiform arrays.
tan to dark brown, 4.5–5.5 mm, apical collars differentiated or not;
pappi 13–23 mm.
dark brown, 3.5–6.5 mm, apical collars not differentiated;
pappi 9–19(–25) mm.
= 32.
Cirsium remotifolium
Cirsium edule
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 3 (3 in the flora).
The edible thistle has had a convoluted nomenclatural history. The labels on the type collection (BM) bear the following information: “Circium [sic] * edule” and “R. Mountains & plains of Columbia.” When Nuttall published the name, he listed the range as “The plains of Oregon and the Blue Mountains.” The type specimen closely resembles plants from western Oregon, but plants of Cirsium edule are not known to occur in the Blue Mountains. J. T. Howell (1943) noted that the name C. edule had long been in use for two distinctly different species, one with a long, slender corolla tube, short lobes, and a barely exserted style and the other with a stouter corolla with a shorter tube, longer lobes, and a long-exserted style. He applied the name C. edule to the species with the slender corolla, and took up the name C. macounii for the second species. After examining the type of C. edule, A. Cronquist (1953) pointed out that Howell had erred in applying that name to the short-styled species, and described the latter as C. brevistylum. Cronquist expressed doubt as to the collection locality of the type of C. edule, focusing on the Blue Mountains and not noting the duality of the location data on the specimen and in Nuttall’s publication. It is likely that the plants Nuttall observed in the Blue Mountains were C. brevistylum.
J. T. Howell (1960b) resurrected the name Cirsium hallii to apply to a group of Oregon thistles growing west of the Cascade Range, attributing to it a type locality of Salem, Oregon. Howell (1943) had noted that he had borrowed “the type” of C. hallii from the Gray Herbarium. This species had been described (as Cnicus hallii) by Gray based upon three syntypes (one each cited from California, Utah, and Oregon). The specimen examined by Howell was apparently the Oregon collection by [Elihu] Hall that Gray cited. The Utah and California specimens are different taxa. After examining photographs of the holotype of C. edule and the Oregon specimen of C. hallii, and various specimens collected in the area that Howell described as the range of C. hallii, I have concluded that C. hallii and C. edule are clearly conspecific.
Cirsium edule is a polymorphic species much in need of an in-depth field-based investigation. R. J. Moore and C. Frankton (1962) noted that in the northern part of its range, C. edule occurs mostly at elevations from 300 to over 2100 m. However, along the Oregon coast the species occurs on sea bluffs a few meters above the surf. Populations from montane sites are often rather different in appearance from those of lowland areas, and coastal plants differ from those of nearby more interior areas. Both montane and strictly coastal plants tend to be compact with heads tightly crowded and usually with very densely arachnoid involucres. Plants of non-montane interior sites tend to be taller and more openly branched. Plants of interior sites in southern Washington and Oregon have smaller heads with less densely arachnoid involucres than those farther to the north or along the seashore. The spiny tips of the phyllaries may be ascending or may radiate from the head forming a dense, spiny ball.
Hybridization may have played a role in the diversification of Cirsium edule. Hybrids between C. edule var. macounii and C. brevistylum in southern Canada have been named as C. ×vancouveriense R. J. Moore & C. Frankton. Cirsium edule and C. brevistylum overlap extensively in parts of their ranges and hybrids may occur throughout their area of sympatry. Some of the variation in the southern part of the range of C. edule may be a result of past introgression with various forms of C. remotifolium.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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. Heads mostly borne singly; peduncles 10–30 cm | var. wenatchense |
1. Heads crowded at stem tips; peduncles usually 0–1 cm | → 2 |
2. Phyllary apices plane to acicular, ascending or ± spreading, spines 1–5 mm | var. edule |
2. Phyllary apices long-acicular, widely spreading, spines 5–15 mm | var. macounii |
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