Blue Cohosh

Blue Cohosh
Blue Cohosh. Caulophyllum giganteum also Caulophyllum thalictroides.
Berberaceae, the barberry family.

Plant: Erect plant, to 12" when flowering, later to as much as 30", growing from an underground rootstock, with much-divided leaves, and producing a cluster of small brownish purple or green flowers.
Flowers: Brownish purple to green, 1/4" - 1/2", with five petal-like sepals, five small, cup-like petals, and five yellow stamens, in a loose cluster (a raceme) generally with 5-10 flowers. The brownish-purple variety has larger flowers and blooms earlier than the green form, and has recently been recognized as a separate species (C. giganteum).
Leaves: The leaves are highly divided. In appearance there is a lower pair, and an upper pair of opposite leaves, pinnately subdivided into often lobed leaflets. Technically these pairs are classified as single leaves, so the plant has only two: an upper and a lower. The leaves of the purple form are deep purple when the plant first emerges and turn green later.
Fruit: A cluster of large blue berries.
Blooming: April-May
Habitat: Deciduous woods

Comments: An early spring flower. The plant is also known as squawroot and is considered a poisonous plant. However, the roots were used by native Americans and early colonists to ease childbirth, and it is still collected for this and other purposes by present-day herbal medicine practitioners, so much so that native populations have been threatened in some locations. Conventional sources explicitly warn pregnant women against consuming this plant, so there may be some actual effect.

Where to find it: I have found only one small patch of these plants in the park, along the upper forest trail.