Caltha leptosepala is morphologically complex, and a number of segregate taxa have been described. Plants are most commonly assigned to two species, however. Caltha leptosepala in the strict sense is found in the Rocky Mountains of Arizona and New Mexico north to Alaska and is characterized by longer-than-broad leaves with small, nonoverlapping basal lobes, solitary-flowered inflorescences, and sessile follicles. Plants in the Coast Ranges of central California north to the coastal islands of southern Alaska, distinguished by broader-than-long leaves with large, overlapping basal lobes, 2-flowered inflorescences, and stipitate follicles, have been called Caltha.biflora . My comparison of specimens from the Rocky Mountains and the Coast Ranges indicated that no clear distinction could be made. While plants are often distinctive in the southern part of their range, a continuous intergradation between the two extremes exists over much of their range[].

Common Name: Western Marsh Marigold

General Information

Caltha leptosepala is a herbaceous perennial plant producing a cluster of basal leaves up to 15cm tall and flowering stems up to 30cm tall[].
The plant is sometimes harvested from the wild for local use as a medicine and, in emergencies, as a food. It is grown as an ornamental in gardens.
The species has a relatively restricted range, but much larger than the thresholds for a threatened category and while it is possibly declining in parts of its range, it is not thought that any global population decline is likely to meet (or be close to meeting) the threshold for Vulnerable. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The whole plant, but especially the older portions, contains the toxic glycoside protoanemonin - this is destroyed by heat[]. Symptoms of poisoning include a burning sensation in the throat, vomiting, bloody diarrhoea, dizziness, fainting, and, in large doses, convulsions. However, the toxicity is of a fairly low order and the plant would usually need to be eaten in quantity in order to cause major symptoms[]
The sap can irritate sensitive skin[].

Botanical References

, ,

Range

Western N. America - Alaska and Yukon, south to California, Arizona and New Mexico

Habitat

Open, wet, subalpine and alpine marshes, wet seepages and marshy meadows; at elevations from 750 - 3,900 metres[, , ].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Habit	Perennial
Height	0.30 m
Pollinators	Bees, Beetles, Flies
Cultivation Status	Ornamental, Wild

Cultivation Details

Caltha leptosepala has a very wide native range, from the Arctic of Alaska to the warm temperate climate of California and New Mexico. It can tolerate temperatures falling to around -20°c[].
A plant of the waterside, it prefers growing in a sunny position in wet soils or shallow water[, , ], though it will tolerate drier conditions if there is shade from the summer sun[]. It requires a deep rich slightly acidic soil[, ]. Grows well in heavy clay soils.
A greedy plant, inhibiting the growth of nearby plants, especially legumes[].

Edible Uses

Root - it must be well cooked[]. A survival food, used when all else fails[]. Some caution is advised, see the notes above on toxicity.

Flower buds - raw, cooked or pickled and used as a caper substitute[, , , ]. Some caution is advised, see the notes above on toxicity.

Young leaves, before the flowers emerge are eaten raw or cooked[, , ]. Some caution is advised, see the notes above on toxicity.
Older leaves, before the plant flowers, can be eaten if well cooked[]. Some caution is advised, see the notes above on toxicity.

Medicinal

The whole plant is antispasmodic and expectorant. It has been used to remove warts[]. A poultice of the chewed roots has been applied to inflamed wounds[].

Other Uses

None known

Propagation

Seed - best sown as soon as it is ripe in a cold frame in late summer[]. Stand the pots in 2 - 3cm of water to keep the soil wet. The seed usually germinates in 1 - 3 months at 15°c[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a tray of water in a cold frame until they are at least 15cm tall. Plant them out into their permanent positions in the summer.
Division in early spring or autumn[]. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the summer or following spring.