Petalostemum is the Greek word meaning "petal and stamen"; so named because of the way the petals and stamens are joined. Purpureum comes from the word for "purple".

Found throughout the Tallgrass Prairie region in native prairies and prairie remnants on dry or well-drained soils. Often found with P. candidum. Blooms from May to September. Not a typical legume flower, having one large petal and four smaller ones. The tiny flowers grow tightly together on the cone at the top of the stem.

This was one of the favored plants of the Native Americans of the prairies. A tea made from the leaves was applied to open wounds and a tea made from the bruised leaves steeped in hot water was used to aid in the healing of wounds as well. Some tribes pulverized the root and made a tea from that powder that was a very healthy drink and a preventative medicine. Some tribes used the entire plant as a prophylactic (medicine which preserves or defends against disease; a preventive). Early settlers mixed the bark of the white oak tree and the flowers of this species to make a medicine for diarrhea. The Ponca tribe was known to chew the roots of prarie clover simply for the pleasant taste. Native American women also gathered the stems of prairie clover and made brooms and brushes from them when dried.

In Europe, especially in Ireland and Scotland, the seeds of prairie clover were ground into a flour. The flour made a very tasty and highly nutritous bread. The Pawnee name for this species literally translates as "broom-weed". Also a valuable forage crop.

Edible Uses: The root was used for chewing. A pleasant sweet flavour.

The dried leaves are a tea substitute.

Medicinal Uses: A poultice of the steeped bruised leaves has been applied to fresh wounds. A decoction of the leaves and blossoms has been used in the treatment of heart problems, diarrhoea. An infusion of the roots has been used in the treatment of measles.

Other Uses: The tough, elastic stems have been made into brooms.

Herbal Uses: Unknown