Cirsium palustre |
Cirsium brevistylum |
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cirse ou chardon des marais, European Marsh thistle, European swamp or marsh thistle, European swamp thistle, marsh thistle |
cluster thistle, Indian or cluster or short-style thistle, Indian thistle, short-style thistle |
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Habit | Biennials or monocarpic perennials, 30–200(–300) cm; clusters of fibrous roots. | Annuals or biennials, 20–350 cm; taprooted. |
Stems | single, erect, villous to tomentose with jointed trichomes, distally tomentose with fine, unbranched trichomes; branches 0–few, ascending, (short). |
usually 1, erect, simple or branched in distal 1/2, loosely to densely villous or viscid-pilose with jointed trichomes, often arachnoid below heads; branches 0–many, ascending. |
Leaves | blades narrowly elliptic to oblanceolate, 15–30+ × 3–10 cm, margins shallowly to very deeply pinnatifid, narrow lobes separated by broad sinuses, spiny-dentate to lobed, main spines 2–6 mm, abaxial villous to tomentose with jointed trichomes, sometimes also thinly tomentose with fine unbranched trichomes, adaxial faces villous with septate trichomes or glabrate; basal often present at flowering, petioles spiny-winged, bases tapered; cauline many, sessile, gradually reduced and becoming widely spaced above, bases long-decurrent with prominently spiny wings; distal cauline deeply pinnatifid with few-toothed spine-tipped lobes. |
blades oblong to elliptic or oblanceolate, 15–35 × 2–10 cm, flat to ± undulate, coarsely dentate to shallowly pinnatifid, lobes broadly triangular, spinulose to spiny-dentate or shallowly lobed, main spines slender, 3–7 mm, abaxial faces thinly gray-tomentose, villous along major veins, sometimes glabrescent, adaxial sparsely villous or viscid-pilose along midveins with jointed trichomes; basal often absent at flowering, spiny winged-petiolate; principal cauline well distributed, gradually reduced, proximal winged-petiolate, mid and distal sessile, bases clasping or short-decurrent; distal moderately to strongly reduced, often spinier than the proximal. |
Peduncles | 0–1 cm. |
0–1(–30) cm. |
Involucres | ovoid to campanulate, 1–1.5 × 0.8–1.3 cm, thinly cobwebby tomentose with fine unbranched trichomes. |
hemispheric to campanulate, 2.5–3.5 cm, 2.5–4 cm diam., loosely to densely arachnoid, phyllaries connected by long septate or non-septate trichomes. |
Corollas | lavender to purple (white), 11–13 mm, tubes 5–7 mm, throats 2–3 mm, lobes 3–4.5 mm; style tips 1.5–2 mm. |
white to pink or purple, very slender, 20–25 mm, tubes 10–17 mm, throats 4–5 mm, lobes filiform with knoblike tips, 3–5 mm; style tips 2–4 mm, included or exserted (only 1–2 mm beyond corolla lobes). |
Phyllaries | in 5–7 series, strongly imbricate, greenish, or with purplish tinge, lanceolate to ovate (outer) or linear-lanceolate (inner), margins thinly arachnoid-ciliate, abaxial faces with narrow glutinous ridge, outer and middle appressed, entire, apices acute, mucronate or spines erect or spreading, weak, 0.3–1 mm; apices of inner phyllaries purplish, linear-attenuate, scarious, flat. |
radiating in 5–10 series, subequal, green, linear-acicular, outermost margins sometimes spiny-fringed, otherwise all entire or minutely serrulate, abaxial faces without glutinous ridge; outer and mid bases short-appressed, apices stiffly radiating to ascending, long, very narrow, spines straight, slender, 3–5 m; apices of inner straight, flat. |
Heads | few–many in dense clusters at branch tips. |
1–many, ± erect, usually crowded in subcapitate to tight corymbiform arrays, closely subtended by clustered ± leafy bracts. |
Cypselae | tan to stramineous, 2.5–3.5 mm, apical collars 0.1–0.2 mm, shiny; pappi 9–11 mm. |
brown, 3–4.5 mm, apical collars stramineous, 0.2 mm; pappi 10–22 mm. |
2n | = 34. |
= 34. |
Cirsium palustre |
Cirsium brevistylum |
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Phenology | Flowering summer (Jul–Aug). | Flowering spring–summer (Apr–Sep). |
Habitat | Marshes, wet forests | Coastal meadows, marshes, swamps, riparian woodlands, moist sites in coastal scrub, chaparral, coastal woodlands, mixed conifer-hardwood forests, or coniferous forests |
Elevation | 10–800 m (0–2600 ft) | 0–1000 m (0–3300 ft) |
Distribution |
MA; MI; NH; NY; WI; BC; NF; NS; ON; QC; SPM; Europe [Introduced in North America]
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CA; ID; MT; OR; WA; BC
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Discussion | Cirsium palustre is a noxious weed, native to Europe, that invasively spreads through wetland communities, forming impenetrable spiny stands as it displaces native species. The range of this pernicious weed in North America is rapidly expanding. It has the potential to spread into boreal forest areas across the continent; in Europe it grows nearly to the Arctic Circle. The rapid spread of C. palustre in Michigan (E. G. Voss 1972–1996, vol. 3) is indicative of its invasiveness. Spontaneous hybrids between C. palustre and C. arvense have been reported from England and other European countries (W. A. Sledge 1975) and can be expected wherever these species grow together in North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cirsium brevistylum occurs in the coast ranges and adjacent coastal slope from southwestern British Columbia to southern California. In the Pacific Northwest its range extends inland to the northern Rocky Mountains of southern British Columbia, Idaho, and northwestern Montana, and the Blue and Wallowa ranges of eastern Oregon. It is absent from the central and southern Cascade Range. In older literature the name Cirsium edule was widely misapplied to this species. A. Cronquist (1953) pointed out that the type of C. edule has corolla and style features quite different from those of the plants that had been called by that name and established the name C. brevistylum, based upon the notably short styles of this species. Hybrids of C. brevistylum with C. edule have been named C. ×vancouveriense R. J. Moore & C. Frankton. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 110. | FNA vol. 19, p. 148. |
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium |
Sibling taxa | ||
Synonyms | Carduus palustris | |
Name authority | (Linnaeus) Scopoli: Fl. Carniol. ed. 2, 2: 128. (1772) | Cronquist: Leafl. W. Bot. 7: 26. (1953) |
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