Mentzelia oligosperma Nutt. ex Sims
Chicken Thief, Stickleaf
Family - Loasaceae
Stem - To 80 cm, branched and sprawling, brittle, densely pubescent with barbed hairs, whitish or gray.
Leaf - Lanceolate to rhombic, coarsely and irregularly toothed or lobed, densely pubescent with barbed hairs.
Pagodaform hairs at leaf base.
Inflorescence - Teminal clusters of a few flowers, or solitary.
Hypanthium - 4-6 mm long, densely pubescent with barbed hairs.
Hypanthium and stamens.
Flower - Sepals 5, deciduous. Petals 5, orange. Stamens 15-40. Staminodes absent.
Fruit - Capsule 7-14 mm long, cylindrical to clavate, densely pubescent with barbed hairs, with 1-3 seeds.
Flowering - June - August.
Habitat - Ledges, bluff tops, glades.
Origin - Native to the U.S.
Other info. - This species is Missouri's only native Mentzelia. The common names refer to the tendency
of the plant parts to adhere tenaciously to fur, feathers, or clothing. A field botanist whom I know has had Mentzelia leaves persist on his
trousers through airline travel and subsequent laundering. This tenacity is caused by the presence of complex hairs bearing
whorls of retrorse barbs. These "pagodaform" hairs are a distinguishing feature of the Mentzelia genus.
Mentzelia oligosperma rewards early-rising
observers with richly colored flowers, which are fully open only in the morning.
Photographs taken at Castlewood State Park, St. Louis County, MO, 8-9-2010, and at Danville Conservation Area, Montgomery County, MO, 8-23-2016 (SRTurner).