''Trifolium microcephalum'' is a species of

clover Clovers, also called trefoils, are plants of the genus ''Trifolium'' (), consisting of about 300 species of flowering plants in the legume family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with the highest diversit ...

known by the common names smallhead clover and small-headed clover. It is native to western North America from southern

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

and

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

, and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, where it occurs in many types of habitat, becoming common to abundant in some regions. It can grow in disturbed habitat and become a casual roadside

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

Description

''Trifolium microcephalum'' is an annual herb taking a decumbent or erect form. It is coated in hairs. The leaves are made up of oval leaflets with notched tips, each measuring up to 2 centimeters long, and bristle-tipped

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...

s. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a head of flowers borne in a bowl-like involucre of wide, hairy

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

s. The head is not more than a centimeter wide. Each flower has a calyx of

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s with lobes narrowing into hairy bristles. The flower corolla is pinkish or purplish and measures 4 to 7 millimeters in length.

References

External links

Calflora Database: ''Trifolium microcephalum'' (Hairy clover, Maiden clover, Small headed clover)Jepson Manual eFlora (TJM2) treatment of ''Trifolium microcephalum''Burke Museum, University of Washington UC CalPhotos gallery: ''Trifolium microcephalum''
microcephalum Flora of British Columbia Flora of California Flora of the Northwestern United States Flora of Arizona Flora of Nevada Flora of the Sierra Nevada (United States) Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Natural history of the Peninsular Ranges Natural history of the Transverse Ranges {{Trifolieae-stub