Flower:

Small, dense clusters at the tips of branching stems and arising from leaf axils in the upper plant. Flowers are yellow, 3/8-½ inch across with 5 petals that are obscurely triangular to heart-shaped, rounded but flattened or slightly depressed at the tip and tapered at the base. Behind the petals is a set of 5 lance shaped sepals alternating with the petals, and another set of alternating bractlets behind them. The relative lengths to each other are diagnostic for the 3 varieties found in Minnesota. See notes below.

Leaves and stems:

Leaves are alternate and pinnately compound with a range of 5 to 13 leaflets depending on the variety (see notes below). The lower leaves are stalked, leaves become smaller and shorter stalked as they ascend the stem. Leaves in the flower cluster may be three parted and stalkless.

The leaflets are generally oblong in outline, variably cleft into linear or oblong lobes, rolled under along the edges. The upper surface is green and smooth or gray-green with long, appressed, silky hairs; the lower surface is semi-smooth or white from dense woolly hairs (tomentose). At the base of each leaf stalk is a pair of lance shaped leafy appendages (stipules). Stems are erect to spreading and ascending, sparsely to densely woolly.

Notes:

In Minnesota, P. pensylvanica is mostly a prairie species of our western counties, with 3 recognized varieties present. The two most prevalent appear to be var. pensylvanica and var. bipinnatifida. The former can be distinguished with having 7 to 13 leaflets, and the flower petals are typically longer than both the bractlets and sepals. The latter has only 5 to 7 leaflets and these are crowded towards the tip of the leaf stalk, nearly palmately compound in appearance, and its flowers petals and bractlets are both shorter than the sepals. The third variety, var. arida, has 7 to 13 lealets like var. pensylvanica, but its leaflets are cleft only half way to the midrib where in var. pensylvanica the clefts typically are over halfway to the midrib. Also in var. arida the bractlets are distinctly longer than both sepals and petals, and the petals often shorter than the sepals.