Distribution
Albania, Algeria, Angola, Argentina (introduced), Austria, Bangladesh, Benin, Botswana, Bulgaria, Burkina Faso, Burundi, Cambodia, Cameroon, Canada (introduced), Cape Verde, Central African Republic, Chad, Chile (introduced), China, Czech Republic, Djibouti, Ecuador (introduced), Egypt, Ethiopia, France, Gambia, Ghana, Greece, Guinea, Hungary, India, Italy, Ivory Coast, Japan, Kazakhstan, Kenya, Kuwait, Kyrgyzstan, Lebanon, Libya, Malawi, Maldives, Mali, Mauritania, Mexico (introduced), Mongolia, Morocco, Mozambique, Myanmar, Namibia, Niger, Nigeria, Oman, Pakistan, Peru (introduced), Portugal, Romania, Rwanda, Saudi Arabia, Senegal, Somalia, South Africa, Spain, Sri Lanka, Sudan, Swaziland, Syria, Taiwan, Tajikistan, Tanzania, Togo, Tunisia, Turkey, Turkmenistan, U.S.A. (introduced), Uganda, Ukraine, Uruguay (introduced), Uzbekistan, Vietnam, Yemen, Zambia, Zimbabwe

Native to: Albania, Algeria, Altay, Angola, Austria, Baleares, Bangladesh, Benin, Botswana, Bulgaria, Burkina, Burundi, Buryatiya, Cambodia, Cameroon, Canary Is., Cape Provinces, Cape Verde, Caprivi Strip, Central African Repu, Central European Rus, Chad, China North-Central, China South-Central, China Southeast, Corse, Czechoslovakia, Djibouti, East Aegean Is., Egypt, Eritrea, Ethiopia, France, Free State, Gambia, Ghana, Greece, Guinea, Gulf States, Hainan, Hungary, India, Inner Mongolia, Italy, Ivory Coast, Japan, Kazakhstan, Kenya, Kirgizstan, Korea, Kriti, Kuwait, KwaZulu-Natal, Lebanon-Syria, Libya, Malawi, Maldives, Mali, Manchuria, Mauritania, Mongolia, Morocco, Mozambique, Mozambique Channel I, Myanmar, Namibia, Niger, Nigeria, Northern Provinces, Oman, Pakistan, Portugal, Qinghai, Romania, Rwanda, Sardegna, Saudi Arabia, Senegal, Sicilia, Sinai, Socotra, Somalia, South China Sea, South European Russi, Spain, Sri Lanka, Sudan, Swaziland, Tadzhikistan, Taiwan, Tanzania, Tibet, Togo, Tunisia, Turkey, Turkey-in-Europe, Turkmenistan, Tuva, Uganda, Ukraine, Uzbekistan, Vietnam, West Siberia, Xinjiang, Yemen, Yugoslavia, Zambia, Zaïre, Zimbabwe.

Introduced into: Alabama, Argentina Northeast, Argentina Northwest, Argentina South, Arizona, Arkansas, Bolivia, British Columbia, California, Chile North, Colorado, Delaware, Ecuador, Florida, Galápagos, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Masachusettes, Mexico Northwest, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Ontario, Oregon, Panamá, Pennsylvania, Peru, Primorye, South Carolina, South Dakota, St.Helena, Tennessee, Texas, Turks-Caicos Is., Uruguay, Utah, Washington, Wisconsin, Wyoming.

Herbs, annual; herbage hairy (whitish), especially young shoots, becoming glabrate. Stems prostrate, green to reddish, to 1 m, ± hirsute, sericeous. Leaves 2-4.5 × 1 cm; stipules 1-5 × to 1 mm; leaflets 6–12(–16), ovate to elliptic, largest 4-11 × 2-4 mm, densely sericeous, younger parts silvery, becoming glabrate. Pedicels shorter to longer than shorter pair of leaves, in flower 2-7 mm, in fruit 5-15 mm, apex bent. Flowers 5(-10) mm diam.; sepals ovate-lanceolate, 2-4 × 1.5-2 mm, minutely ciliate, hirsute; petals oblong, 2.5-5 × 1-3 mm; outer whorl of nectary glands yellowish, inner whorl distinct, yellow, triangular, 0.2 mm; stamen filaments 2-3 mm; anthers yellow, cordate, 1 mm; ovary 1-5 mm diam.; style 5-ridged, cylindric, stout, 1-1.5 mm; stigma globose. Schizocarps (7-)10-15 mm diam. excluding 4-12 mm spines; mericarps bearing 2 conic spreading 3–7 mm dorsal spines and sometimes 2 smaller retrorse spines near base, body green to gray or yellowish, hispid, strigose, or glabrate.
Flowering Mar-Oct. Agricultural lands, roadsides, railways, other disturbed areas; 0-2300 m.