Asteraceae
Swamp thistle
Cirsium muticum
- Family
- Asteraceae
- Genus
- Cirsium
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Common names
By language (1)
- English
- Swamp thistle, Dunce-nettle
Synonyms
- Carduus muticus Pers.
- Carduus muticus var. albiflorus Farw.
- Carduus muticus var. muticus
- Carduus muticus var. subpinnatifidus Britton
- Cirsium bigelowii DC.
- Cirsium muticum f. lactiflorum Fernald
- Cirsium muticum f. monticola (Fernald) B.Boivin
- Cirsium muticum f. muticum
- Cirsium muticum var. monticola Fernald
- Cirsium muticum var. muticum
- Cirsium muticum var. subpinnatifidum Fernald
- Cnicus glaber Nutt.
- Cnicus glutinosus Bigelow
- Cnicus muticus Elliott
- Cnicus muticus (Michx.) Pursh
- Cnicus muticus var. alpicola Britton & A.Br.
- Cnicus muticus var. monticola Fernald
- Cnicus muticus var. muticus
Flowers
- In flower
- July to September (from 509 flowering iNaturalist observations worldwide)
Characteristics
- Growth habit
- Forb/herb
- Lifespan
- Biennial
- In the US and Canada
- Canada: native, Lower 48 states: native, St. Pierre and Miquelon: native
Photos
FlowerPhoto: Nathan Aaron, CC BY 4.0, from iNaturalist 
FlowerPhoto: Tom Scavo, CC BY 4.0, from iNaturalist 
FlowerPhoto: Douglas Goldman, CC BY-SA 4.0, from iNaturalist 
Photo: Superior National Forest, CC BY 2.0, from Wikimedia Commons 
Photo: Tom Scavo, CC BY 4.0, from iNaturalist 
Photo: Superior National Forest, CC BY 2.0, from Wikimedia Commons Photo: Bingley Joshua, CC BY-SA 4.0, from Pl@ntNet via GBIF 
Photo: naturalist charlie, CC BY 4.0, from iNaturalist 
Photo: Ayotte, Gilles, 1948-, CC BY-SA 4.0, from Wikimedia Commons Photo: Dani Hooven, CC BY-SA 4.0, from Pl@ntNet via GBIF 
Photo: Bonnie Semmling, CC BY 4.0, from iNaturalist 
Photo: Ayotte, Gilles, 1948-, CC BY-SA 4.0, from Wikimedia Commons
More in Cirsium
- Creeping thistleCirsium arvenseAsteraceae
- Spear thistleCirsium vulgareAsteraceae
- Marsh thistleCirsium palustreAsteraceae
- Cabbage thistleCirsium oleraceumAsteraceae
- Dwarf thistleCirsium acauleAsteraceae
- Woolly thistleCirsium eriophorumAsteraceae
- Melancholy thistleCirsium heterophyllumAsteraceae
- Cirsium rivulareAsteraceae
- Meadow thistleCirsium dissectumAsteraceae
- Yellow melancholy thistleCirsium erisithalesAsteraceae
- Cirsium spinosissimumAsteraceae
- Cirsium tuberosumAsteraceae
Sources: classification, synonyms from World Flora Online Plant List (2026-06, CC0 1.0); common names, popularity from Wikidata (2026-10-26, CC0 1.0); common names, US characteristics from USDA PLANTS Database (2025-05-29, CC0 1.0). About our plant data.