Caulophyllum thalictroides (L.) Michx. - Blue Cohosh

Caulophyllum thalictroides plant

Family - Berberidaceae

Stems - From rhizomes, to +/-50cm tall, erect, herbaceous, multiple from the base, glaucous, terete, green with purple at the base, glabrous.

Leaves - Mostly one leaf per stem, triternate. Leaflets 3(4-5)-lobed a the apex, entire, glabrous, 4-5cm long, +/-3cm broad. Lobes of the leaflets acute, with a small whitish apex. Main veins of the leaflets arising from the base of the leaflet. All veins impressed above, expressed below. Lateral leaflets often oblique at the base.

Caulophyllum thalictroides leafletAdaxial surface of leaf.

Culophyllum thalictroides leafletAbaxial surface of leaf.

Inflorescence - Axillary panicle to +4cm long. Peduncle to +3cm long, glabrous. Ech division of the panicle subtended a minute bract. Bracts 1-2mm long, acute, scarious on the margins.

Caulophyllum thalictroides inflorescence

Flowers - Petaloid sepals 6, yellow-green, spatulate, rounded at the apex, +/-5mm long, 2-3mm broad, with slightly darker veins, distinct. Petals smaller than the sepals, green, glabrous, hooded, 2mm long, 2mm broad at the apex. Stamens 6, ascending. Filaments green, glabrous, 1.5mm long. Anthers yellow, 1mm long, 1mm broad, bi-lobed. Ovary green, obovoid, glabrous, +2mm long, -2mm broad, slightly 3-sided, unilocular, with 3 ovules, tapering into a -1mm long style. Stigma minute. Placentation basal.

Caulophyllum thalictroides flowerFlower close-up.

Flowering - March - May.

Habitat - Rich woods in valleys, ravines, north-facing wooded slopes, moist base of bluffs.

Origin - Native to U.S. and Asia.

Other info. - This species can be found scattered throughout most of Missouri but is generally found in the eastern half of the state. The plant can be identified in the field by its glaucous stems, ternately divided leaves (the leaf picture above is of just the terminal division of a leaf), its greenish flowers, and its brilliant blue seeds (which I have no pictures of at this time). The plant also has a thick root which was used medicinally by natives. A tea made from the root was used to treat a variety of ailments such as abdominal cramps, urinary tract infections, and problems with the uterus. The roots may also have contraceptive properties. The root of the plant contains glycosides and alkaloids and many people get a reaction from handling the roots. The seeds of the plant are toxic and should not be eaten.

Photographs taken at Earthquake Hollow Conservation Area, Callaway County, MO., 4-13-04.


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