Found throughout the temperate northern hemisphere, yellow marsh marigolds (Caltha palustris, Ranunculaceae) can be a common sight in marshes, fens, ditches, and around ponds and other wet areas. Earlier this week I came across quite a few of them in the marshy areas surrounding Losee Lake at Pinckney State Recreation Area near Chelsea, Michigan.
These plants can easily be identified by their wet growing conditions, rounded and bluntly-serrated leaves, and large yellow flowers. The flowers most often bear five petals, but can have anywhere from four to nine. Their flowering period starts early in the spring, making them an important source of nectar and pollen for newly-emerging insects.
In spite of having the common name “marigold,” these plants aren’t related to true marigolds. Marsh marigolds are in the buttercup family (Ranunculaceae) while true marigolds are asters (Asteraceae). As with many other members of the buttercup family, marsh marigolds can cause irritation to the skin and mucous membranes if handled excessively, and can cause gastrointestinal cramps if eaten raw.