1. Caulophyllum thalictroides (L.) Michx. (blue cohosh)
Pl. 301 h–j; Map
1272
Plants perennial
herbs, with rhizomes 5–7 mm thick. Aerial stems 40–60 cm tall, without spines.
Leaves cauline, 2 per plant, often not fully expanded at flowering time; lower
leaf 3 times ternately compound, 20–32 cm long, usually sessile, occasionally
with a petiole to 4.5 cm long; upper leaf twice ternate, 8.5–14.0 cm long. Leaflets
obovate, sometimes 2- or 3-parted, and generally with a few rounded teeth, the
upper surface green, the lower surface glaucous. Inflorescences terminal, open
clusters or small panicles of 4–16 flowers, 13–60 mm long, sometimes with a
second inflorescence in the axil of the upper leaf. Flowers with 3 or 4
sepal-like bracts immediately below the calyx. Sepals 6, 3–5 mm long, yellow,
purple, or green. Petals 6, 1–2 mm long, yellow, purple, or green, bearing
nectaries. Stamens 6, anthers attached at the base, opening by 2 apical flaps.
Fruit wall rupturing early in development to expose the developing seeds. Seeds
1 or 2 per fruit, 6–9 mm long, spherical, each on a thick stalk 4–7 mm long,
the seed coat fleshy, blue, glaucous. 2n=16. April–May.
Scattered nearly
throughout Missouri, but less common in the western half of the state (New
Brunswick south to northern Georgia, west to Arkansas and southern Manitoba).
Mesic upland forests, often on rich slopes in ravines, bottomland forests, and
shaded ledges of bluffs.
Rootstocks of
blue cohosh were used medicinally by Native Americans for a variety of
treatments, including rheumatism, toothaches, menstrual problems, and various
ailments of the digestive and urinary tracts (Moerman, 1998). The berrylike
seeds are considered poisonous and the plants rarely can cause dermatitis in
some people.