The marsh marigold is also called cowslip, kingcup, meadow-gowan, water-dragon, may blobs, soldiers-buttons, water-goggles.
The marigold, a perennial, is one of the showy members of the buttercup family, with its abundant yellow flowers and luxuriant foliage. The stems are smooth, hollow, and furrowed. The leaves are round or kidney-shaped, with a slightly scalloped or even margin. There are no petals, but the broad, bright sepals take their place. The stamens are numerous. The seed pods are somewhat flattened, spreading, short -beaked, and many-seeded. The plant is in flower from April till June.
The marsh marigold is a native of Canada, and is-found in swamps, wet meadows, and along streams from Newfoundland to Saskatchewan.
Like most of the species of buttercup, the marsh marigold contains acrid poisonous properties, and both man and animals have suffered. Cattle have died from eating it, although as a general rule, they, as well as sheep, avoid it unless urged by hunger. Miller reports the poisoning of several horses, one of which succumbed. When in a young state the plant is harmless and is eaten boiled as greens, but' Cornevin states that it becomes toxic by the time of blooming and that the toxicity increases with maturity. If eaten after the flower buds have unfolded, it is likely to cause extreme nausea and pain in the abdomen. A. B. Smith holds that the toxicity is due to the alkaloid jervine and the glucoside helleborin.
When dried with the hay, according to H. C. Long, the plant is harmless, but Rusby states it causes diarrhoea and loss of milk production.
According to Cornevin the symptoms are similar to those produced by buttercup poisoning, i. e. diarrhoea, loss of milk production, colic, bloating, inflammation of the bladder, etc. Johnson and Sowerby mention the case of five persons who, after eating marsh marigold as a herb, were "seized with violent sickness and pain in the abdomen, followed by diarrhoea and general oedematous swelling over the whole body."
The western species, no doubt, contain similar poisonous properties and should be viewed with suspicion, although no cases of poisoning have been reported.
The yellow marsh-marigold (Caltha asarifolia DC.) is the only western species with yellow flowers. It resembles the eastern species in general appearance, and is found in marshy meadows in British Columbia and the Yukon.
The mountain marsh-marigold (C. leptosepala DC.) has white flowers, usually tinged with blue on the outside. It grows in wet alpine meadows in Alberta, British Columbia, and the Yukon. The two-flowered species (C. biflora DC.) has numerous stem leaves and white flowers with one stalk shorter than the other. The dwarf marsh-marigold (C. chelidonii Greene grows from two to four inches high. Its leaves are round, heart-shaped and its flowers white. It is found along alpine streams and below the snow.