Cirsium palustre |
Cirsium repandum |
|
---|---|---|
cirse ou chardon des marais, European Marsh thistle, European swamp or marsh thistle, European swamp thistle, marsh thistle |
coastal-plain thistle, sand-Hill thistle |
|
Habit | Biennials or monocarpic perennials, 30–200(–300) cm; clusters of fibrous roots. | Perennials, 20–80 cm; creeping roots deep-seated, sometimes appearing as taprooted biennials. |
Stems | single, erect, villous to tomentose with jointed trichomes, distally tomentose with fine, unbranched trichomes; branches 0–few, ascending, (short). |
1–several, spreading to erect, (usually very leafy in distal 1/2), loosely arachnoid, and villous with jointed, multicellular trichomes; branches 0–few from above middle, 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. |
linear to oblong or oblanceolate, 6–16 × 1–3.5 cm, unlobed to sinuate-dentate or shallowly pinnatifid, main spines 1–4 mm, fine, faces ± green, shaggy-villous with septate trichomes, abaxial loosely arachnoid when young; basal and proximal cauline usually absent at time of flowering; mid and distal nearly uniform in size or gradually reduced, bases clasping; distalmost cauline ± bractlike. |
Peduncles | 0–1 cm. |
0–2 cm. |
Involucres | ovoid to campanulate, 1–1.5 × 0.8–1.3 cm, thinly cobwebby tomentose with fine unbranched trichomes. |
ovoid or cylindric to campanulate, 2–4 × 1.5–4 cm, loosely arachnoid, ± glabrate. |
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. |
light purple, 33–40 mm, tubes 14–15 mm, throats 12–15 mm, lobes 7–9 mm; style tips 4.5–6 mm. |
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. |
in 6–9 series, imbricate, lanceolate (outer) to linear (inner), abaxial faces with glutinous ridge, outer and middle tightly appressed, bodies scabrous or spinulose, spines erect or weakly ascending, 1–4 mm; apices of inner phyllaries long-acuminate, spineless. |
Heads | few–many in dense clusters at branch tips. |
1–5, in corymbiform arrays. |
Cypselae | tan to stramineous, 2.5–3.5 mm, apical collars 0.1–0.2 mm, shiny; pappi 9–11 mm. |
light brown, 3.5–4 mm, apical collars yellowish, ca. 0.8 mm; pappi 15–30 mm. |
2n | = 34. |
= 30. |
Cirsium palustre |
Cirsium repandum |
|
Phenology | Flowering summer (Jul–Aug). | Flowering spring–summer (May–Jul). |
Habitat | Marshes, wet forests | Sandhills, pine barrens, roadsides |
Elevation | 10–800 m (0–2600 ft) | 0–150 m (0–500 ft) |
Distribution |
MA; MI; NH; NY; WI; BC; NF; NS; ON; QC; SPM; Europe [Introduced in North America]
|
GA; NC; SC; VA
|
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 repandum occurs on the Atlantic coastal plain. R. J. Moore and C. Frankton (1969) suggested that Cirsium repandum originated through ancient hybridization between C. pumilum var. pumilum and C. horridulum. They noted that an artificial hybrid (2n = 32) between C. repandum (2n = 30) and C. horridulum (2n = 34) had a mosaic of features of the parental taxa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 110. | FNA vol. 19, p. 113. |
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium |
Sibling taxa | ||
Synonyms | Carduus palustris | Carduus repandus |
Name authority | (Linnaeus) Scopoli: Fl. Carniol. ed. 2, 2: 128. (1772) | Michaux: Fl. Bor.-Amer. 2: 89. (1803) |
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