Ranunculaceae, the buttercup or crowfoot family.
Plant: Tall, branching plant, to 3', but often shorter, with deeply lobed basal leaves and shiny, bright yellow flowers. Perennial.
Flowers: Bright yellow, 3/4"-1", with five shiny petals, five sepals, and many stamens, organized in a sparse, branching cluster, (a cyme).
Leaves: Mostly basal, 1"-3" wide, deeply and palmately divided into unstalked segments, overall shape round to kidney-shaped. Basal leaves are long-petioled. Sparse upper leaves are much smaller, and sessile.
Fruit: A rounded cluster of dry achenes.
Habitat: Fields, roadsides, waste places.
A European introduction, this species is common in fields and roadsides.
The juice is acrid and irritating to the skin, which accounts for the specific name,
and the is plant somewhat toxic overall.
Drying seems to remove the toxic component, so that livestock may safely consume hay
The Bulbous Buttercup (R. bulbosus), has a very similar flower and habit, but
can be distinguished by the leaves, which are distinctly three-lobed,
the terminal one having a distinct stalk. The leaves of the Common buttercup, in contrast,
are palmately lobed, but not split into stalked leaflets.
The bulbous buttercup can also be distinguished by the bulbous root, but that requires digging
and possibly damaging the plant.
Where to find it:
Common in lower fields of the park. The Bulbous buttercup also grow here, but prefers
the drier hillsides.