''Trifolium thompsonii'' is a species of flowering plant in the legume family known by the common name Thompson's clover. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

in the United States, where it occurs in two counties.''Trifolium thompsonii''.
Center for Plant Conservation.''Trifolium thompsonii''.
NatureServe. One of the largest populations occurs in the Entiat Slopes Natural Area Preserve in Chelan County.Washington State Department of Natural Resources
Entiat Slopes NAP.
Accessed April 13, 2014. This is a large

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

with a thick stem growing up to 60 centimeters tall. The leaves are divided into three to eight serrated leaflets. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

is a round head of several bright red-lavender flowers. Blooming occurs in May through July. Pollinators include bumblebees and the Greenish Blue, a butterfly. This species grows in several types of habitat. One study identified four

plant association A plant community is a collection or association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The components of each plant ...

s that include the clover. The ''

Pseudotsuga menziesii The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...

''/'' Calamagrostis rubescens'' forest habitat is a cooler, moister area with associated species such as ''

Spiraea betulifolia ''Spiraea'' , sometimes spelled spirea in common names, and commonly known as meadowsweets or steeplebushes, is a genus of about 80 to 100 species

'', '' Penstemon fruticosus'', ''

Balsamorhiza sagittata ''Balsamorhiza sagittata'' is a North American species of flowering plant in the tribe Heliantheae of the family Asteraceae known by the common name Arrowleaf Balsamroot. It is widespread across western Canada and much of the western United Stat ...

'', and ''

Achillea millefolium ''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Other common names include old man's pepper, devil's nettle, sanguinary, milfoil, soldier's woundwort, and thousand seal. The ...

''. The '' Artemisia vaseyana''/'' Agropyron spicatum'' association includes ''

Artemisia tripartita ''Artemisia tripartita'' is a species of flowering plant in the aster family known by the common name threetip sagebrush. It is native to western North America from British Columbia to Nevada and Montana to Colorado. It covers about 8.4 million ...

'', ''

Poa secunda ''Poa secunda'' (variously known by the common names of Sandberg bluegrass, alkali bluegrass, big bluegrass, Canby's bluegrass, Nevada bluegrass, one-sided bluegrass, Pacific bluegrass, pine blugrass, slender bluegrass, wild bluegrass, and curly ...

'', and ''

Festuca idahoensis ''Festuca idahoensis'' is a species of grass known by the common names Idaho fescue and blue bunchgrass. It is native to western North America, where it is widespread and common. It can be found in many ecosystems, from shady forests to open plai ...

''. A third association, the '' Pinus ponderosa''/''Agropyron spicatum'' has sparse tree cover, a grass

understory In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abo ...

, and no tall shrubs. Associated species include ''

Eriogonum heracleoides ''Eriogonum heracleoides'' (common names; parsnipflower buckwheat, whorled buckwheat, and Wyeth buckwheat) is a plant of western North America that has many flowering clusters which are usually cream colored, or off-white. It can usually be found ...

'', '' Phlox longifolia'', '' Haplopappus stenophyllus'', and '' Antennaria rosea''. The ''

Artemisia tridentata ''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...

''/''Agropyron spicatum'' association is a drier habitat which includes many

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

s such as '' Allium acuminatum'', '' Agoseris grandiflora'', '' Lomatium nudicaule'', and ''

Lupinus sericeus ''Lupinus sericeus'' is a species of flowering plant in the legume family known by the common name silky lupine or Pursh's silky lupine. It is native to western North America from British Columbia to Arizona and east to Alberta and Colorado. Th ...

''.Scherer, G., et al. (1996)
Habitat characteristics and morphological differences of ''Trifolium thompsonii'' populations.
''Northwest Science'' 70(3) 242-51. A

Research Natural Area Research Natural Area is a designation for certain protected areas in the United States. Research Natural Areas (RNAs) are part of a nationwide network of ecological areas set aside for both research and education. The network includes areas ma ...

, the Thompson Clover Research Natural Area, was established in 1977 in the

Wenatchee National Forest Wenatchee National Forest is a U.S. National Forest located in Washington (state), Washington. With an area of 1,735,394 acres (2,711.55 sq mi, or 7,022.89 km²), it extends about 137 miles along the eastern slopes of the Cascade Range of Wa ...

for the study and protection of this species.Thompson Clover Research Natural Area.

References

External links

Washington Burke Museum
{{Taxonbar, from=Q7841552 thompsonii Flora of Washington (state)