Dalea purpurea

It is native to central North America, where it occurs from central Canada to the southeastern and southwestern United States, except for the east and west coasts. In 1804, Meriwether Lewis collected a specimen in Nebraska. ==Description==

Dalea purpurea is a perennial herb growing tall. The mature plant has a large taproot deep. The stem is woody with several branches. The leaves are a few centimeters long and are divided into 3 to 7 narrow leaflets. The inflorescence atop each stem branch is a spike up to long containing many purple flowers. The fruit is a legume pod containing 1 or 2 seeds. ==Ecology==

This plant is adapted to a habitat with periodic wildfires. In some areas, it depends on fire to clear encroaching woody vegetation, as it cannot tolerate shade. It is a larval host to the southern dogface (Zerene cesonia). ==Uses==

This species is used for revegetation efforts on reclaimed land, such as land that has been strip mined. It is good for preventing erosion and for fixing nitrogen in soil. Though it is often found in mid- to late-successional stages of ecological succession, it may also be a pioneer species, taking hold in bare and disturbed habitat, such as roadsides. Medicinal plant Dalea purpurea has been found to contain several active constituents, including pawhuskin A, pawhuskin B, pawhuskin C, and petalostemumol. The pawhuskins possess affinity for the opioid receptors, and pawhuskin A, by far the most potent of the group, acts as a non-selective antagonist of all three opioid receptors, with preference for the κ- and μ-opioid receptors over the δ-opioid receptor. ==References==