''Cirsium discolor'', the field thistle, is a

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 ...

n species of plants in the tribe

Cardueae The Cardueae are a tribe of flowering plants in the daisy family (Asteraceae) and the subfamily Carduoideae. Most of them are commonly known as thistles; four of the best known genera are '' Carduus'', '' Cynara'' (containing the widely eaten ar ...

within the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

. It is native to thirty-three states in the United States as well four Canadian provinces. It occurs across much of eastern and central Canada as well as eastern and central

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It has been found from

New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...

west to

Saskatchewan Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on t ...

and south as far as

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

and Georgia. Field thistle is a biennial or perennial herb up to tall, producing a large taproot. There is usually only one stem with numerous spiny leaves that are green on the upper side but white and woolly underneath. The plant's

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 ...

are large and showy and have the pale to medium value purplish magenta coloration (lilac, lavender, pinkish purple, purplish pink) that is especially attractive to butterflies. The same color can be seen in the flowers of the genus ''

Liatris ''Liatris'' (), commonly known as gayfeather and blazing star. is a genus of flowering plants in the tribe Eupatorieae within the family Asteraceae native to North America (Canada, United States, Mexico and the Bahamas). Some species are used ...

'', among many others. Heads have many

disc floret The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

s but no ray florets. The species grows primarily in damp areas in forest openings, prairies, and disturbed sites.Flora of North America, Field thistle, chardon discolore, ''Cirsium discolor'' (Muhlenberg ex Willdenow) Sprengel
/ref> It is used as a component of some North American prairie and wildflower meadow restoration mixes that focus on the use of native species. Like most other thistles, it is a food plant for the caterpillars of the Painted Lady butterfly. Most thistles produce a large quantity of nectar and pollen. The large flower heads make them attractive to large butterflies like migrating monarchs. Bumblebees also make use of thistles, gathering the pollen. Hummingbirds sometimes gather nectar from them. This species is of similar size, height, and appearance to the

Bull Thistle ''Cirsium vulgare'', the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus ''Cirsium'', native throughout most of Europe (north to 66°N, locally 68°N), Western Asia (east to the Yenisei Valley), and North Afr ...

, but it is less spiny, has whitish leaf undersides, and, unlike Bull Thistle, often has quite pale flowers. Many thistle species are monocarpic. This means that the plant will flower once and then die. Reproduction of this flower is dependent on seed distribution. This includes interaction with insects, habitat, and weather conditions. FieldThistleInSpring1920X1024

References

https://xerces.org/wp-content/uploads/2016/10/2016-029_Native-Thistle-Conservation-Guidelines_FINAL_web.pdf

External links

*
Lady Bird Johnson Wildflower Center, University of TexasPhoto of herbarium specimen at Missouri Botanical Garden, collected in Missouri, showing leaves
Cirsium, discolor Plants described in 1803 Flora of North America {{Cynareae-stub