Swamp thistle

Cirsium muticum

''Cirsium muticum'', also known as swamp thistle, marsh thistle, dunce-nettle, or horsetops, is a North American species of plants in the sunflower family, native to central and eastern Canada and the central and eastern United States.
Cirsium muticum (Swamp Thistle) Cob-web hairs and thornless bracts of the flower heads help to distinguish this species from Cirsium vulgare and Cirsium arvense. In a low spot at the head of a trail through a restored fen. Also present in the fen. Angiosperms,Asteraceae,Cirsium muticum,Geotagged,Summer,Swamp thistle,United States,fen,flower,wetland

Appearance

''Cirsium muticum'' is a biennial plant that reaches a height of 180 centimetres . Its taproot is fleshy and its stem is ridged with hairs toward the base. The leaves are alternate in position, pinnately lobed, and ovate in shape. The leaf lobes are often asymmetrical and forked irregularly with the angles containing fine trichomes . The leaves become progressively smaller towards the inflorescence; there are often a few trichomes on the underside. The peduncles are 0–15 cm , each with an inflorescence made up of many tiny florets; the involucre has cobwebby white hairs, and it is often slightly sticky. The purple florets can be up to 27 mm long.
Swamp Thistle (Cirsium muticum) Growing at a dense mixed forest edge.
https://www.jungledragon.com/image/71380/swamp_thistle_cirsium_muticum.html Cirsium muticum,Geotagged,Spring,United States,muticum

Naming

''Cirsium muticum'' was described by the French naturalist André Michaux in 1803. It is one of many species in the thistle genus ''Cirsium''. The epithet muticum, meaning blunt, refers to its phyllaries.
Swamp Thistle (Cirsium muticum) Growing at a dense mixed forest edge.
https://www.jungledragon.com/image/71381/swamp_thistle_cirsium_muticum.html Cirsium muticum,Geotagged,Spring,United States,muticum

Distribution

''Cirsium muticum'' has been found across every province of Canada from Labrador and Newfoundland to Saskatchewan. In the United States, it grows primarily in the Northeast, the Great Lakes region, and the Appalachians, with isolated populations scattered across the South from Texas to the Carolinas.

''Cirsium muticum'' is found mostly in alkaline swamps, wetlands, marshes and low forests but some races have been known to grow in wet alpine climates.

Status

The plant is not endangered in Canada or the U.S. but it is threatened in the state of Arkansas, and vulnerable in the province of Saskatchewan. ''Cirsium muticum'' is at risk primarily because it is a wetland plant, and North American wetlands have been much reduced in extent over the last two centuries.

Habitat

''Cirsium muticum'' has been found across every province of Canada from Labrador and Newfoundland to Saskatchewan. In the United States, it grows primarily in the Northeast, the Great Lakes region, and the Appalachians, with isolated populations scattered across the South from Texas to the Carolinas.

''Cirsium muticum'' is found mostly in alkaline swamps, wetlands, marshes and low forests but some races have been known to grow in wet alpine climates.''Cirsium muticum'' is as host for some species of butterflies and moths, including the swamp metalmark butterfly , a species that is currently undergoing risk assessment in the United States. The butterfly lays its eggs on the swamp thistle, and when the eggs hatch, the flowers are the only food source for the caterpillars. Species that grow with it include ''Aster umbellatus'' , ''Solidago patula'' , ''Lysimachia quadrifolia'' , and ''Gentiana procera'' .

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Taxonomy
KingdomPlantae
DivisionAngiosperms
ClassEudicots
OrderAsterales
FamilyAsteraceae
GenusCirsium
SpeciesC. muticum