FWS Focus

Overview

Characteristics
Overview

The Pitcher’s thistle (Cirsium pitcheri) is one of many rare or declining species inhabiting dunes of the Great Lakes region. This distinctive dune plant, often referred to as the dune thistle, was first noted by Dr. Zina Pitcher about 1827 at the Grand Sable Dunes of the Upper Peninsula of Michigan. Pitcher’s thistle is a monocarpic (flowers and sets seed only once), perennial, herbaceous plant, generally flowering after a 5-8 year juvenile stage. The stems and leaves of juveniles and adults are woolly-white, and the leaves are deeply pinnatifid with the lobes less than 1 centimeter
(cm) wide and up to 4 cm long.

Scientific Name

Cirsium pitcheri
Common Name
Pitcher's thistle
sand dune thistle
FWS Category
Flowering Plants
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

The Pitcher’s thistle is a native thistle that grows on the open sand dunes and low open beach ridges along the shorelines of Lakes Michigan, Superior, and Huron. It is now found in Indiana, Michigan, and Wisconsin and in Ontario Canada. Pitcher’s thistle was extirpated from Illinois but has been reintroduced in Lake County. It is most often found in near-shore plant communities but it can grow in all nonforested areas of a dune system.

Pitcher’s thistle is endemic to the beaches and grassland dunes of Lakes Michigan, Superior, and Huron . The majority of known sites of Cirsium pitcheri occur along the shores of Lake Michigan. The species ranges from the north shore of Lake Superior south to Indiana, and formerly occurred in northern Illinois, where it is has been experimentally reintroduced.

Coastal

The land near a shore.

Characteristic category

Life Cycle

Characteristics
Life Cycle

Pitcher’s thistle colonizes patches of open, windblown areas of the landscape, and gradually declines locally as the density of vegetation and ground litter increases through plant succession.

Seed dispersal commences in late July at the northern limits of its range, but can occur from June to August. Primary seed dispersal is through individual seeds blowing from the inflorescence head or by the whole plant and heads falling to the ground at the end of the flowering season.

Once conditions are right, the seed dormancy is broken by cold, moist stratification, with seed germination occurring in May and June. Seedlings produce 1 to 6 leaves in the first season, and then juveniles grow or maintain a constant size throughout the growing season, but may diminish in size over the winter. 

Age of reproduction ranges from 5 to 8 years and appears to be correlated with habitat. Pitcher’s thistle blooms from May to September, with the date of peak bloom occurring later with increasing latitude (mid-July at Sleeping Bear Dunes). 

Life Span

Pitcher’s thistle appears to have a small between-year seedbank, with seeds remaining viable for about three years. This suggests a buried seedbank may not strongly buffer population stability when plants are destroyed. Seed dispersal to nearby suitable habitats may be more important for population stability than the seedbank.

This monocarpic (once-flowering) plant produces a vigorous rosette that may mature for ca. 5-8 years or more before it flowers.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

The stout, prickly, dune species, Pitcher’s thistle, grows for five to eight years before it flowers. Its non-flowering form is a rosette or cluster of silvery leaves and its flowering form typically has one stem with many branches. The entire flowering plant may grow 3 feet tall, but can also be as little as 6 inches and flower. Cream or pink flowers grow at the end of branches and from the leaf axils. Leaves are finely and deeply lobed and may be one foot long.

Color & Pattern

The leaves and entire plant are blue-green in color and densely covered with white-woolly hairs. The mature leaves are deeply divided into narrow, spine-tipped segments. The prickly, spine-tipped flower heads are relatively large and strikingly cream-colored, though they may occasionally have a slightly pinkish tint, yielding seeds with feathery bristles. Pitcher's thistle is unlikely to be easily confused with any other thistle species in Michigan, including both native and nonnative species, all of which can be distinguished by their deep pink flower heads. Pitcher's thistle are unlikely to co-occur with other thistles, as Pitcher's thistle only persist in good quality, open dunes habitat. Vegetatively, all other thistles in Michigan lack the deep blue-green color of Pitcher's thistle and its usually dense covering of white woolly hairs. 

Characteristic category

Food

Characteristics
Food

Geography

Characteristics
Range

The species ranges from the north shore of Lake Superior south to Indiana, and formerly occurred in northern Illinois, where it is has been experimentally reintroduced. Distribution of the species extends along the Lake Michigan shoreline in Wisconsin. In the east it ranges through northern Lake Huron to the Manitoulin Island archipelago and southern Georgian Bay in Ontario. Pitcher’s thistle extends as far south as Lambton County, Ontario, Canada on Lake Huron, as indicated by pre-1964 collections for two localities.

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Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

6 Items

Listing

Listing

Recovery Plan

Five Year Review

Five Year Review

Five Year Review

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Listing

Jul 20, 1987

Jul 20, 1987 Listing (Threatened)
Thr. Status for Cirsium pitcheri; 52 FR 27229-27232
  • Publication type: Proposed
Item 1

Listing

Jul 18, 1988

Jul 18, 1988 Listing (Threatened)
Determination of Thr. Status for Cirsium Pitcheri; 53 FR 27137-27141
  • Publication type: Final
Item 2

Recovery Plan

Oct 11, 2002

Oct 11, 2002 Recovery Plan (Document Availability (non-FR))
Notice of Availability of the Approved Recovery Plan for the Pitcher's Thistle (Cirsium pitcher…
  • Publication type: Final
Item 3

Five Year Review

Mar 30, 2006

Mar 30, 2006 Five Year Review (Information Solicitation)
5-Year Review of Five Midwestern Species
  • Publication type: Notice
Item 4

Five Year Review

Sep 14, 2010

Sep 14, 2010 Five Year Review (Information Solicitation)
5-Year Status Reviews of Seven Midwest Species; Notice of initiation of reviews; request for informa…
  • Publication type: Notice
Item 5

Five Year Review

Jul 8, 2014

Jul 8, 2014 Five Year Review (Information Solicitation)
Initiation of 5-Year Status Reviews of Nine Listed Animal and Two Listed Plant Species
  • Publication type: Notice
Item 6