''Cirsium pitcheri'', sometimes called Pitcher's thistle or dune thistle, is a species of

thistle Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. ...

native to

sand dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...

shorelines along the upper

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

. It is native to

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

, and

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

. It is listed by the

U.S. Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with oth ...

as a

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...

Description

Pitcher's thistle is a plant of modest appearance through much of its lifespan; it concentrates most of its biomass in a massive

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

that can be 6 feet (2 m) in length. Its long, narrow, gray-green leaves are protected by spines and dense, silvery hairs. Between 2 and 8 years after germination, the juvenile thistle abruptly matures and sends forth a flower stalk of 100 cm (40 inches) or more in height. At the top of the blooming shoot is a spectacular effusive

flower head 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 ...

, ranging in color from creamy white to very light pink, and guarded by spines. Some individuals may be quite bushy, and produce numerous flowering heads. Usually at least 5 years are required for the thistle to reach maturity. Pitcher's thistle is

monocarpic Monocarpic plants are those that flower and set seeds only once, and then die. The term is derived from Greek (''mono'', "single" + ''karpos'', "fruit" or "grain"), and was first used by Alphonse de Candolle. Other terms with the same meaning are ...

; after flowering once, the plant dies. Most of its seeds do not disperse very far, in fact, entire heads are occasionally buried, producing clusters of seedlings. The Pitcher's thistle is adapted to life on open, windswept, semi-stable sand dune surfaces. It can flower at any time from mid-June through mid-September, depending on the amount of energy it has stored in its taproot and on local rain conditions immediately prior to the flowering.

History and identification

The Pitcher's thistle was first identified by Dr.

Zina Pitcher Zina Pitcher (April 12, 1797, in Sandy Hill, New York – April 5, 1872, in Detroit) was an American physician, politician, educator, and academic administrator. He was a president of the American Medical Association, a two-time mayor of Detroi ...

, an amateur naturalist and

U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

field surgeon stationed at

Fort Brady Fort Brady was a frontier fort established in Sault Sainte Marie, Michigan to guard against British incursions from Canada. The original location of the fort, known as Old Fort Brady, was along the Saint Mary's River. Fort Brady was located at ...

Sault Ste. Marie, Michigan Sault Ste. Marie ( ') is the only city in, and county seat of, Chippewa County, Michigan, Chippewa County in the U.S. state of Michigan. With a population of 13,337 at the 2020 United States census, 2020 census, it is the second-most populated ...

. In an unknown summer at some point in the 1820s, Dr. Pitcher was granted leave to go on an adventure camping trip west of the fort on a sandy shoreline of

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...

. While exploring what are now the Grand Sable Dunes of the

Pictured Rocks National Lakeshore Pictured Rocks National Lakeshore is a U.S. National Lakeshore in the Upper Peninsula of Michigan, United States. It extends for 42 miles (67 km) along the shore of Lake Superior and covers . The park has extensive views of the hilly sho ...

, Dr. Pitcher discovered a Pitcher's thistle in flower. The physician shipped the specimen to botanists who published and named it in his honor, ''Cirsium pitcheri''.

Distribution

The Pitcher's thistle is found exclusively along the shorelines of

Lake Huron Lake Huron ( ) is one of the five Great Lakes of North America. Hydrology, Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as Lake Michigan, to which it is connected by the , Strait ...

Lake Michigan Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and the third-largest by surface area (), after Lake Superior and Lake Huron. To the east, its basin is conjoined with that o ...

, and

, particularly in areas of sand dunes.Biota of North America Program 2014 county distribution map
/ref> Two of the largest remaining populations have been identified in the Nordhouse Dunes area of the

Manistee National Forest The Manistee National Forest is a national forest located in the Lower Peninsula of Michigan. It has a total area of . It was established in 1938, and combined with the Huron National Forest in 1945 for administrative purposes, creating the Huro ...

, and within

Sleeping Bear Dunes National Lakeshore Sleeping Bear Dunes National Lakeshore is a United States National Lakeshore located along the northwest coast of the Lower Peninsula of Michigan in Leelanau and Benzie counties near Empire, Michigan. The park covers a stretch of Lake Michig ...

. In addition, Pitcher's thistle continues to grow and flower in some smaller state parks and private tracts along these lake shores.

Conservation

dune habitat is threatened by invasive species such as

spotted knapweed ''Centaurea stoebe'', the spotted knapweed or panicled knapweed, is a species of ''Centaurea'' native to eastern Europe, although it has spread to North America, where it is considered an invasive species. It forms a tumbleweed, helping to increa ...

. In addition, the high economic value of Great lakes shoreline for

real estate development Real estate development, or property development, is a business process, encompassing activities that range from the renovation and re-lease of existing buildings to the purchase of raw Real Estate, land and the sale of developed land or parcels ...

continues to threaten the Pitcher's thistle. Although it can be locally abundant in areas of relatively undisturbed habitat, the thistle is highly vulnerable because it is adapted to live in locations where many people would like to build vacation

home A home, or domicile, is a space used as a permanent or semi-permanent residence for one or many humans, and sometimes various companion animals. It is a fully or semi sheltered space and can have both interior and exterior aspects to it. H ...

s and

resort A resort (North American English) is a self-contained commercial establishment that tries to provide most of a vacationer's wants, such as food, drink, swimming, lodging, sports, entertainment, and shopping, on the premises. The term ''resort ...

s and is therefore critically threatened by anthropogenic

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

. This fact, as well as its general vulnerability due to its specialized habitat and restricted range, has led to Pitcher's Thistle being federally listed as a threatened species by the U.S. government; it is also listed as either threatened or endangered at the state level. In Canada it is listed as endangered at both the provincial (Ontario) and federal level.Ontario's Biodiversity: Species at Risk - Pitcher's Thistle.
Accessed 11 February 2011.

References

External links

2001; Michigan Department of Natural Resources, Lansing, Mich. Accessed 11 February 2011.
''C. pitcheri''.
The Nature Conservancy.
''C. pitcheri''.
Center for Plant Conservation. {{Taxonbar, from=Q5122070 pitcheri Plants described in 1829 Flora of the Great Lakes region (North America)