Plant of the Week

Map of the United States showing states. States are colored green where the species may be found.
Range map of tansyleaf suncup. Map from USDA PLANTS Database.

Tansyleaf Suncup  in flower.
Tansyleaf suncup late summer in a vernal wetland. Photo by Cheryl Beyer, Modoc National Forest Botanist.

Tansyleaf Suncup (Camissonia tanacetifolia (Torr. & A. Gray) P.H. Raven)

By Forest Jay Gauna

Suncup is a name generally applied to plants of the genus Camissonia, and an apt one. The bright yellow four-petaled flowers indeed have the appearance of capturing some of the sun’s brightness in a little cup. The Latin name honors a Franco-German naturalist who explored California on a Russian expedition; the state flower of California, Eschcholzia californica, was named by him for a friend on the same expedition.

Suncup was formerly included in the genus Oenothera, and both are in the Onagraceae, or evening primrose family. Known for showy flowers, this family features Fuschias, Clarkias, willowherbs, and evening primroses, which are common garden flowers.

Suncup may be found in open areas, such as meadows or fields. The soils are clay and the ground is moist at least part of the year. In northeastern Calfornia, it is a vernal pool species. During the summer, a dried vernal pool can look like a yellow lake from a distance, with all of the flowers blooming at the same time. The illusion is aided by the fact that the plants are very low-growing, hugging the ground. Upon reaching the lake of yellow, thousands of small plants are found growing at about toe height: they are perennials with a tough woody root, from whence come several leaves, a few inches long, that are highly dissected or lobed. This is the origin of the specific name tanacetifolia, which means in Latin "leaves like a tansy." They resemble feathers.

The flowers are fairly typical of those in this family. There are four green sepals bent backwards at the base (reflexed). Above them are four bright yellow petals, each a little less than an inch long. There are eight yellow stamens and one central yellow style, taller than the stamens, with a little knobby tip.

Besides being a range wildflower, this plant has few uses to humankind. It seems to have had a minor medicinal use to the Navajo.

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