Showy Partridge Pea

Media
Photo of showy partridge pea showing flowers, buds, and leaves.
Scientific Name
Chamaecrista fasciculata (formerly Cassia fasciculata)
Family
Fabaceae (beans, peas)
Description

Showy partridge pea is an annual with upright stems, usually without branches. Flowers 1 to several, about 1 inch across, arising from leaf axils. Petals 5, yellow (rarely white), sometimes reddish-tinged at the base; one side petal curves around the stamens; the lowest petal is the largest. Blooms July–October. Leaves compound, pinnately divided, with up to 18 leaflets that are narrow, short, linear. Leaflets fold up along the midrib at night into a sleeping position, and often upon being touched. Fruit a legume (short beanlike pod) 1–2½ inches long, black when mature. When mature and dry, the two sides separate suddenly, flinging the seeds a yard or more away.

Similar species: Small-flowered, or sensitive partridge pea (C. nictitans) is about half as tall, branches a bit more, and has inconspicuous flowers no bigger than about ½ inch wide. It grows mostly south of the Missouri River.

Size
Height: commonly to 2 feet, sometimes nearly 3 feet.
Where To Find
image of Showy Partridge Pea distribution map
Scattered to common nearly statewide.
Occurs in fields, pastures, waste places, roadsides, and railroads, as well as glades, upland prairies, openings in upland forests, savannas, ledges and tops of bluffs, and banks of streams and rivers. Partridge pea is one of the most commonly seen roadside plants of early fall. Nyctinasty, the plant’s tendency to close up its leaflets at night, is thought to be an adaption to control water loss or afford protection from herbivores. Many members of the bean family exhibit this characteristic.
This plant has incredibly interesting flowers, and people enjoy figuring out how they work. The special arrangement of flower parts, for example, encourages what is called “buzz pollination” by bumblebees, and ants visiting nectar glands in the leaf stems remove the plant’s insect pests.
Our two partridge pea species are important wildlife food plants and are sometimes planted for this purpose. Deer and livestock eat the nutritious foliage, though some compounds in the plant can cause digestive upset if too much is eaten. Quail, turkey, and other birds are fond of the seeds.
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Where to See Species

Prairie Home Conservation Area, located in eastern Cooper County, is an upland area with a mix of oldfields, small cropfields, grasslands, and woodlands. The original acquisition in 1963 included 212
About Wildflowers, Grasses and Other Nonwoody Plants in Missouri
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!