Actaea racemosa L.

Black Cohosh

Actaea racemosa plant

Family - Ranunculaceae

Stems - Flowering stems to +2m tall, erect, glabrous, glaucous, from a woody caudex, herbaceous, green but purple at the nodes.

Actaea racemosa nodePurple node.

Leaves - Basal and alternate, petiolate, glabrous, to 1m broad, -1m long, ternately divided, purple at the joints. Ultimate leaflets serrate, green adaxially, silvery-green abaxially, with a few hairs abaxially on the veins. Serrations of margin with a lighter green or yellowish apex. Veins of leaflets impressed adaxially. Leaves of the flowering stem reduced to bracts.

Actaea racemosa leafLeaf.

Inflorescence - Terminal and axillary racemes to +/-50cm long. Axis of the inflorescence tomentoulose. Pedicels to 6cm long in flower, slightly longer in fruit, whitish tomentose. Each pedicel subtended by a minute bract. Bracts attenuate, 1-3mm long.

Actaea racemosa inflorescenceInflorescence

Actaea racemosa inflorescenceInflorescence

Flowers - Apetalous, Asepalous, fetid. Stamens many, +/-100. Filaments white, filiform, glabrous, to 5mm long. Anthers white, 1mm long. Ovary superior, white, tomentose, obliquely ovoid, 2.5mm long in flower, unilocular, with +/-10 ovules. Style wanting, forming a slight beak in fruit. Seeds semicircular in shape.

Actaea racemosa flowerIndividual flower.

Flowering - May - August.

Habitat - Low rocky woods, base of bluffs.

Origin - Native to U.S.

Other info. - This distinctive species can be found in the Ozark region of Missouri. When in bloom, the plant is easy to ID in the field because of its big leaves and long inflorescences. The plant also has a foul odor, especially when in flower.
This species has many medicinal uses. Traditionally, a tincture of the plant was used for bronchitis, chorea, fevers, rheumatism, snakebites, and many other ailments. Modern medicine has found the plant useful for strengthening female reproductive organs in lab rats. The plant has also shown anti-inflammatory properties.

Photographs taken at the Current River Conservation Area, Reynolds County, MO., 6-26-01, and at Big Spring Park, MO., 7-1-03 (DETenaglia); also at Johnson's Shut-Ins, Reynolds County, MO, 6-26-2015 (SRTurner).