Flora of North America species comparison

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Cirsium palustre

Cirsium ownbeyi

cirse ou chardon des marais, European Marsh thistle, European swamp or marsh thistle, European swamp thistle, marsh thistle

Ownbey's thistle
Habit Biennials or monocarpic perennials, 30–200(–300) cm; clusters of fibrous roots. Perennials, 30–70 cm; taproots and branched caudices with persistent dark-brown leaf bases.
Stems

single, erect, villous to tomentose with jointed trichomes, distally tomentose with fine, unbranched trichomes;

branches 0–few, ascending, (short).

1–several, erect, simple or sparingly branched in distal 1/2, glabrous or thinly arachnoid and sparingly villous with jointed trichomes.
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, 15–30+ × 2–7 cm, deeply 2–3-pinnately divided, lobes linear to linear-lanceolate, spinulose to spiny-dentate or shallowly lobed, main spines slender, 2–8 mm, abaxial faces glabrous to thinly tomentose and villous along major veins, soon glabrescent, adaxial glabrous;

basal present at flowering, narrowly spiny winged-petiolate;

principal cauline well distributed, proximal winged-petiolate, mid and distal sessile, gradually reduced, bases decurrent as spiny wings 1–3 cm;

distalmost reduced to spiny-pectinate bracts.
Peduncles

0–1 cm.

0–4 cm.
Involucres

ovoid to campanulate, 1–1.5 × 0.8–1.3 cm, thinly cobwebby tomentose with fine unbranched trichomes.

ovoid, 1.8–2.5 cm, 1.5–2.5 cm diam., 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.

white to pink or pink-purple, 16–20 mm, tubes 6–8 mm, throats 5–6 mm, lobes 5–7 mm;

style tips 3.5–4.5 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 5–6 series, imbricate, green, linear-lanceolate, abaxial faces without or with poorly developed glutinous ridge;

outer and mid bases appressed, apices stiffly radiating to ascending, long, very narrow, entire, spines slender, 3–10 mm;

apices of inner straight, flexuous.
Heads

few–many in dense clusters at branch tips.

1–few, erect, ± crowded in corymbiform arrays.
Cypselae

tan to stramineous, 2.5–3.5 mm, apical collars 0.1–0.2 mm, shiny;

pappi 9–11 mm.

brown, ca. 4 mm, apical collars not differentiated;

pappi 13–17 mm.
2n

= 34.

Cirsium palustre

Cirsium ownbeyi
Phenology Flowering summer (Jul–Aug). Flowering summer (Jun–Aug).
Habitat Marshes, wet forests Stony soils in sparsely vegetated areas of pinyon-juniper woodlands, sagebrush scrub, arid grasslands, and riparian scrub, in dry sites or sometimes on seeps
Elevation 10–800 m (0–2600 ft) 1500–2400 m (4900–7900 ft)
Distribution
from FNA
MA; MI; NH; NY; WI; BC; NF; NS; ON; QC; SPM; Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; UT; WY
[BONAP county map]
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 ownbeyi is endemic to the eastern side of the Uintah Mountains in northeastern Utah, southwestern Wyoming, and northwestern Colorado. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 19, p. 110. FNA vol. 19, p. 153.
Parent taxa Asteraceae > tribe Cardueae > Cirsium Asteraceae > tribe Cardueae > Cirsium
Sibling taxa
C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. engelmannii, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. engelmannii, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. palustre, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
Synonyms Carduus palustris
Name authority (Linnaeus) Scopoli: Fl. Carniol. ed. 2, 2: 128. (1772) S. L. Welsh: Great Basin Naturalist 42: 200. (1982)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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