''Trifolium microcephalum'' is a species of

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 ...

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

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...

and

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

, and

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, 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, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

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). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

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, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or o ...

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 The term ''sepalum'' was coine ...

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