The flower of Ranunculus acris............May 2002.
Meadow buttercup is also known as tall buttercup. It has one to several erect and freely branching stems from 30-80 cm high. The stems are hollow and do not root at the nodes if they touch the ground. The herbage ranges from sparsely to abundantly hirsutely haired. The basal leaves are large and roughly heart-shaped in outline, the margins deeply parted into 3-5 lobes. The individual lobes are again deeply parted so that the leaf appears almost dissected (See photo below.). The blades range from 3-8 cm long and the petioles are up to 20 cm long. The stem leaves are reduced in size upwards on the stem and alternate along the stem. These consist of 3-5 narrow, linear lobes.
The inflorescence is open. The 5 greenish sepals are covered with light hairs and 4-6 mm long. The sepals quickly drop after flowering. The 5 petals are yellow and measure 10-14 mm long and about 5-7 mm wide. The stamens number 30-70.
Meadow buttercup may be found on most to well-drained soils at lower elevations.
Meadow buttercup is a weedy species introduced from Europe. It is now widely established across the United States and Canada. In the west, it may be found from Alaska south to California and eastward to Idaho and Montana.
The photo above illustrates a leaf from midstem of meadow buttercup. Gresham, OR...........May, 12, 2002.