Pitcher's thistle
Encyclopedia
The Pitcher's thistle sometimes called dune thistle, is a species of thistle
native to sand dune shorelines along the upper Great Lakes
. It grows endemically only in Indiana
, Michigan
, Wisconsin
, and Ontario
. It is listed by the U.S. Fish and Wildlife Service as a threatened species
.
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 to 8 years after germination, the juvenile thistle abruptly matures and sends forth a temporary blooming head of 1 m 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
; 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.
, a field surgeon of the U.S. Army station at Fort Brady
, located at the present Sault Ste. Marie, Michigan
. 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
. While exploring what are now the Grand Sable Dunes of the Pictured Rocks National Lakeshore
, 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.
The Pitcher's thistle is found exclusively along the shorelines of Lake Huron
, Lake Michigan
, and Lake Superior
, particularly in areas of sand dunes. Two of the largest remaining populations have been identified in the Nordhouse Dunes
area of the Manistee National Forest, and within Sleeping Bear Dunes National Lakeshore
. In addition, Pitcher's thistle continues to grow and flower in some smaller state parks and private tracts along these lake shores.
U.S. Great Lakes 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
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
s and resort
s and is therefore critically threatened by anthropogenic habitat destruction
. 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.
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 often occur all over the plant – on surfaces such as those of the stem and flat parts of leaves. These are an adaptation that protects the...
native to sand dune shorelines along the upper Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
. It grows endemically only in Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, and Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
. It is listed by the U.S. Fish and Wildlife Service as a threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
.
Niche
Pitcher's thistle is a plant of modest appearance through much of its lifespan; it concentrates most of its biomass in a massive taprootTaproot
A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...
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 to 8 years after germination, the juvenile thistle abruptly matures and sends forth a temporary blooming head of 1 m 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
Monocarpic plants are those that flower, set seeds and then die. Other terms with the same meaning are hapaxanth and semelparous. The term was first used by Alphonse de Candolle....
; 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 PitcherZina Pitcher
Zina Pitcher was an American physician, politician, educator, and academic administrator. He was a president of the American Medical Association, a two-time mayor of Detroit and a member of the Board of Regents of the University of Michigan.-Early life:Zina Pitcher was born in Sandy Hill, New York...
, a field surgeon of the U.S. Army station at Fort Brady
Fort Brady
Colonel Hugh Brady established Fort Brady at Sault Sainte Marie, Michigan Territory in 1822 to guard against British incursions from Canada.The garrison at the fort protected exclusive American sovereignty over the northern frontier...
, located at the present Sault Ste. Marie, Michigan
Sault Ste. Marie, Michigan
Sault Ste. Marie is a city in and the county seat of Chippewa County in the U.S. state of Michigan. It is in the north-eastern end of Michigan's Upper Peninsula, on the Canadian border, separated from its twin city of Sault Ste. Marie, Ontario, by the St. Marys River...
. 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
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...
. While exploring what are now the Grand Sable Dunes of the Pictured Rocks National Lakeshore
Pictured Rocks National Lakeshore
Pictured Rocks National Lakeshore is a U.S. National Lakeshore on the shore of Lake Superior in the Upper Peninsula of Michigan, United States. It extends for 42 miles along the shore and covers...
, 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.
Today
Lake Huron
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
, Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
, and Lake Superior
Lake Superior
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...
, particularly in areas of sand dunes. Two of the largest remaining populations have been identified in the Nordhouse Dunes
Nordhouse Dunes Wilderness
The Nordhouse Dunes Wilderness is a listed wilderness area within the Manistee National Forest. It is located north of Ludington, Michigan, and is best known for its 4 miles of undeveloped Lake Michigan shoreline.-Geology:...
area of the Manistee National Forest, and within Sleeping Bear Dunes National Lakeshore
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 County and Benzie County....
. In addition, Pitcher's thistle continues to grow and flower in some smaller state parks and private tracts along these lake shores.
U.S. Great Lakes 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
Real estate development, or Property Development, is a multifaceted business, encompassing activities that range from the renovation and re-lease of existing buildings to the purchase of raw land and the sale of improved land or parcels to others...
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
Home
A home is a place of residence or refuge. When it refers to a building, it is usually a place in which an individual or a family can rest and store personal property. Most modern-day households contain sanitary facilities and a means of preparing food. Animals have their own homes as well, either...
s and resort
Resort
A resort is a place used for relaxation or recreation, attracting visitors for holidays or vacations. Resorts are places, towns or sometimes commercial establishment operated by a single company....
s and is therefore critically threatened by anthropogenic habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
. 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.
External links
- Pitcher's thistle: distribution and habitat. 2001; Michigan Department of Natural Resources, Lansing, Mich. Accessed 11 February 2011.
- C. pitcheri. The Nature Conservancy.
- C. pitcheri. USDA Plants Profile.
- C. pitcheri. Center for Plant Conservation.