Cirsium joannae |
Cirsium palustre |
|
---|---|---|
Joanna's thistle |
cirse ou chardon des marais, European Marsh thistle, European swamp or marsh thistle, European swamp thistle, marsh thistle |
|
Habit | Perennials, 100–150 cm; caudices taprooted. | Biennials or monocarpic perennials, 30–200(–300) cm; clusters of fibrous roots. |
Stems | 1, fleshy, erect, openly branched in distal 1/2, glabrous; branches on distal stems several, ascending. |
single, erect, villous to tomentose with jointed trichomes, distally tomentose with fine, unbranched trichomes; branches 0–few, ascending, (short). |
Leaves | blades oblong, 10–50 × 6–12 cm, margins usually not strongly undulate, coarsely dentate or shallowly to deeply pinnatifid with 10–15 pairs of lobes, teeth or lobes ± closely spaced, not much overlapping, narrowly to broadly triangular, spiny-dentate or larger shallowly 3–5-lobed, main spines 2–12 mm, abaxial faces glabrous, adaxial glabrous; basal present at flowering, petiolate or spiny winged-petiolate; principal cauline many, well distributed, proximally ± winged-petiolate, distally sessile, gradually reduced, less divided, bases auriculate-claping and/or decurrent as spiny wings to 2 cm; distal much reduced. |
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. |
Peduncles | 0–2 cm Involucres green, ovoid to campanulate (not including spreading phyllary apices), 2.5–4 × 2.5–3.5 cm, appearing glabrous. |
0–1 cm. |
Involucres | ovoid to campanulate, 1–1.5 × 0.8–1.3 cm, thinly cobwebby tomentose with fine unbranched trichomes. |
|
Corollas | lavender-pink, 20–26 mm, tubes 5–8.5 mm, throats 5.2–8 mm, lobes linear, 9–10 mm; style tips 3.5–4.2 mm, conspicuously exserted beyond corolla lobes. |
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. |
Phyllaries | in 5–7 series, unequal, outer longer than inner, bases short-appressed, abaxial faces without glutinous ridge, minutely scabridulous, apices green, thick, spreading to curved-ascending, proximally flattened, linear, spines stout, 5–12 mm; outer entire or pinnately spiny, inner entire, scabridulous-ciliolate; apices of inner flexuous, sometimes slightly expanded and minutely erose. |
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. |
Heads | several–many, erect or nodding, usually sessile or short-pedunculate, crowded in subcaptitate or short, spiciform clusters at branch tips, collectively forming open, paniculiform arrays. |
few–many in dense clusters at branch tips. |
Cypselae | dark brown, 4.5–5 mm, apical collars not differeniated; pappi ca. 20 mm. |
tan to stramineous, 2.5–3.5 mm, apical collars 0.1–0.2 mm, shiny; pappi 9–11 mm. |
2n | = 34. |
|
Cirsium joannae |
Cirsium palustre |
|
Phenology | Flowering summer (Aug–Sep). | Flowering summer (Jul–Aug). |
Habitat | Hanging gardens with Lobelia, Abies, and Adiantum | Marshes, wet forests |
Elevation | 1700 m (5600 ft) | 10–800 m (0–2600 ft) |
Distribution |
UT |
MA; MI; NH; NY; WI; BC; NF; NS; ON; QC; SPM; Europe [Introduced in North America]
|
Discussion | Cirsium joannae is endemic to Zion National Park in southwestern Utah. It apears to be most closely related to C. rydbergii, which occurs in similar habitats in southeastern Utah and northeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 19, p. 163. | FNA vol. 19, p. 110. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Carduus palustris | |
Name authority | S. L. Welsh: in S. L. Welsh et al., Utah Fl. ed. 3, 168. (2003) | (Linnaeus) Scopoli: Fl. Carniol. ed. 2, 2: 128. (1772) |
Web links |