Pennsylvania Buttercup (Ranunculus pensylvanicus): yellow Minnesota wildflowers

Pennsylvania Buttercup

Plant Info
Also known as:	Bristly Buttercup, Bristly Crowfoot
Scientific name:	Ranunculus pensylvanicus
Family:	Buttercup (Ranunculaceae)
Life cycle:	annual, short-lived perennial
Origin:	native
Habitat:	sun to part shade; wet fields, ditches, marshes, along shores
Bloom season:	summer
Plant height:	1 to 3 feet
USDA PLANTS database:	Minnesota county distribution map
Spotted in Ramsey County at:	Long Lake Regional Park Vadnais/Snail Lake Regional Park

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Flower:: Flowers are at the end of stems the arise from the leaf axils near the top of the plant. Individual flowers are 1/8 to ¼ inch across with 5 shiny yellow rounded petals. There is a ring of yellow-tipped stamen around a bulbous yellowish center that turns bright green with maturity. One plant has a few to many flowers.
Leaves and stem:: Leaves are compound in 3's, with leaflets (usually) deeply divided into 3 wedge-shaped to elliptical segments that are further lobed, notched and/or coarsely toothed. Leaflets are up to 3 inches long and 2 inches wide, becoming smaller as they ascend the stem, and are hairy. Attachment is alternate.
Leaves near the base of the plant have long stems that sheath the main stem. These often die and fall off early. The main stem and leaf stems are both densely covered in stiff hairs, becoming more sparsely hairy with age.
Fruit:: Fruit is a cylindrical head of 60 to 80 flatten seeds, each with a pointed “beak”.
Notes:: There are several species of buttercup with small yellow flowers. The leaves are pretty distinct for each species, and is a good way to tell them apart. Little-leaf Buttercup has smaller variable shaped leaves, with kidney-shaped basal leaves; it grows in the woods in early spring. Hooked Buttercup has larger, broader leaves and it also grows earlier in the season. The flower petals of both those species are narrower and more pointed.