''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 characterized by leaves with sharp spikes 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. T ...

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, flat ...

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 spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

. It is native to

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

, and

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

. It is listed by the U.S. Fish and Wildlife Service as a

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

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 taproot ...

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, 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 (', "single" + , "fruit" or "grain"), and was first used by Alphonse de Candolle. Other terms with the same meaning are '' hapaxanth'' ...

; 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, an amateur

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

and

U.S. Army The United States Army (USA) is the primary land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of the United Stat ...

field surgeon stationed at Fort Brady,

Sault Ste. Marie, Michigan Sault Ste. Marie ( ') is a city in the Upper Peninsula of Michigan, Upper Peninsula of the U.S. state of Michigan. It is the county seat of Chippewa County, Michigan, Chippewa County and is the only city within the county. With a population of ...

. 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 is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. Lake Michigan–Huron has a larger combined surface area than Superior, but is normally considered tw ...

. 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, Upper Peninsula of Michigan, United States. It extends for along the shore of Lake Superior and covers . The park has extensive views of the h ...

, 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. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French ex ...

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 depth () after Lake Superior and the third-largest by surface area (), after Lake Superior and Lake Huron. To the ...

, 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 U.S. national lakeshore in the northwestern Lower Peninsula of Michigan. Located within Benzie and Leelanau counties, the park extends along a stretch of Lake Michigan's eastern coastline, as well ...

. 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. 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 parce ...

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 more human occupants, and sometimes various companion animals. Homes provide sheltered spaces, for instance rooms, where domestic activity can be p ...

s and

resort A resort (North American English) is a self-contained commercial establishment that aims to provide most of a vacationer's needs. This includes food, drink, swimming, accommodation, sports, entertainment and shopping, on the premises. A hotel ...

s and is therefore critically threatened by anthropogenic

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

. 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)