''Cirsium scariosum'' is a species of
thistle known by the common names meadow thistle, elk thistle and dwarf thistle. It is native to much of western
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
from
Alberta and
British Columbia, south to
Baja California. There are also isolated populations on the Canadian
Atlantic Coast, on the
Mingan Archipelago
The Mingan Archipelago is an archipelago located east of Quebec, Canada. It consists of a chain of about 40 islands.
Starting but 124 miles from the end of the road along the north shore of the St. Lawrence River (Le Fleuve), the Mingan Archipela ...
in
Québec
Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...
,
[Flora of North America, Meadow or elk thistle, chardon écailleux, ''Cirsium scariosum'' Nuttall]
/ref> where it is called the ''Mingan thistle''.
Description
''Cirsium scariosum'' is a variable species growing in a variety of habitat types. It is made up of several geographic races, most of which have been previously classified as species.[ The races intergrade but their morphologies can also be quite different. This is generally a biennial or perennial herb. It takes three main forms, a stemless, flat rosette with a cluster of ]flower heads
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...
in the centre, a mounding form with a short, erect stem, or a fully erect form reaching up to in height. When there is a stem it is usually fleshy, ridged, and woolly in texture. The leaves are sharply toothed or cut into toothed lobes, lined with spines, and up to at their longest near the base of the plant. The inflorescence holds several flower heads
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...
, each up to 4 centimeters long and 5 cm wide. The flower head is lined with phyllaries which may have spines and teeth and filled with white to purple disc florets but no ray florets. The fruit is a compressed achene
An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...
a few millimetres long topped with a pappus which may be 3 centimeters in length.[
]
Varieties
As accepted by Flora of North America
The ''Flora of North America North of Mexico'' (usually referred to as ''FNA'') is a multivolume work describing the native plants and naturalized plants of North America, including the United States, Canada, St. Pierre and Miquelon, and Greenla ...
;[
*''Cirsium scariosum'' var. ''americanum'' - California, Colorado, Idaho, Nevada, Oregon, Utah, Wyoming, Baja California
*''Cirsium scariosum'' var. ''citrinum'' - California, Baja California ]
References
External links
Jepson Manual TreatmentCalphotos Photo gallery, University of California
scariosum
Plants described in 1841
Flora of North America
Taxa named by Thomas Nuttall
{{Cynareae-stub