Bur buttercup

Occurrence:
Bur buttercup seeds germinate in early spring, when temperatures reach about 41°F, and seedlings emerge soon thereafter. The plant blooms within 3 weeks of emergence, and the flowers develop into spiny burs. By early summer, the entire plant dries out and turns brown and brittle.

Description:
A low-growing summer annual, ranging from 1/2 inch to 5 inches in height. The light green leaves, which are covered with short, white hairs, grow 1-4 inches long. Leaves are all attached at the base of the plant, and many bear a resemblance to antlers, being parted into three distinct, narrow segments, which are themselves often two, three or four-lobed. Flowers are borne singly at the tips of leafless stalks, which extend above the leaves. The tiny, bright yellow, five-petalled flowers are cupped by five egg-shaped sepals. Flowers give rise to oval-shaped, spiny burs that are 1/2 - 3/4 inch long. Each bur contains 5-80 hard, dry seeds.

Weedy Characteristics:
Bur buttercup reproduces from seed. The spiny burs that house the seeds readily cling to shoes, clothing and animal fur. The lightweight burs are also easily picked up and carried by water, and are widely distributed. The plant is very adaptable, and will tolerate moist to very dry conditions. In addition, bur buttercup often forms associations with soil fungi that enable it to take up nutrients very efficiently, allowing it to grow in poor quality soils. Without competition, the plant can form dense carpets.