Scientific Name - Cirsium pitcheri
Range - The Pitcher’s thistle is a native thistle that grows
on the beaches and grassland dunes 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.
Appearance - The 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. 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. The stems and leaves
of both the flowering and non-flowering forms are covered with white hairs
that give the plant a woolly white or silvery appearance. These hairs
are an adaptation to its beach environment and help the plant retain water
and reflect the sun’s strong rays. Spines are found along the edges
of leaves near the base and at the tips of some of the lobes. Both non-flowering
and flowering plants have a long taproot, up to 6 feet long.
Habitat - Pitcher’s thistle grows on the open sand dunes
and low open beach ridges of the Great Lakes’ shores. It is most
often found in near-shore plant communities but it can grow in all nonforested
areas of a dune system.
Reproduction - The Pitcher’s thistle blooms and sets seed
once during its lifetime, after a five to eight year (i.e., juvenile)
non-flowering period. It then blooms from June to September. The blooms
are pollinated by insects. Thirty species of insects, mainly bees, have
been observed visiting Pitcher’s thistle blossoms. After the seeds
mature, they fall or are windblown and germinate the following spring
and early summer. Pitcher’s thistle tends to colonize open areas
or areas with low plant cover.
Why is the Pitcher's thistle
threatened?
Shoreline Development - Residential, condominium, and marina development
along with associated landscaping directly eliminates Pitcher’s thistle
and its habitat within the footprint of the development. Such development
also fragments remaining populations and dune habitats.
Road Maintenance and Construction - Construction of
coastal roads removes and fragments sand dune habitat, alters dune processes,
provides access for destructive recreational activities, and spurs shoreline
development.
Shoreline Recreation Activities - People are drawn to shorelines
for their beauty and recreational opportunities so the remaining shoreline
areas with dune habitat are often also public use areas. Hikers and Off
Road Vehicles (ORVs) trample Pitcher’s thistle which harms or destroys
the plants. ORV traffic in dunes also causes erosion which creates unstable
areas where it’s difficult for plants to take hold. Pitcher’s
thistle and its dune habitat are also destroyed for the creation and maintenance
of public beaches.
What is being done to prevent
the extinction of the Pitcher's thistle?
Listing - Pitcher’s thistle was added to the List of Endangered
and Threatened Wildlife and Plants on July 18, 1988.
Landowner Contacts - Michigan and Wisconsin have landowner contact
programs to educate private and public property owners about this species
needs and ways that it can be conserved.
Project Planning - In areas where the Pitcher’s thistle
is found it is considered during project planning for federally funded
or authorized projects such as marina development and road construction.
Means of avoiding or minimizing harm to the species is often possible
when it is considered during project planning.
What can I do to prevent the
extinction of species?
Learn - Learn more about the Pitcher’s thistle and other
endangered and threatened species. Understand how the destruction of habitat
leads to loss of endangered and threatened species and plant and animal
diversity. Tell others about what you have learned.
Plant Natives - Use native plants in landscaping and gardening
and avoid the use of invasive plants that have been imported from other
countries, such as purple loosestrife, dames rocket, and the shrub honeysuckles.
Conserve - When recreating in coastal areas, drive vehicles only
where authorized and when hiking stay on established or authorized footpaths
to avoid harming rare plants like Pitcher’s thistle and damaging
fragile natural dune areas.
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Pitcher’s thistle
is a threatened species. Threatened species are animals and plants
that are likely to become endangered in the foreseeable future. Endangered
species are animals and plants that are in danger of becoming extinct.
Identifying, protecting and restoring endangered and threatened species
is the primary objective of the U.S. Fish and Wildlife Service’s
endangered species program.