Smallanthus uvedalia (L.) Mack.

Bearsfoot; Small-Flowered Leafcup

Smallanthus uvedalia plant

Family - Asteraceae

Stems - No info. yet.

Smallanthus uvedalia stem

Leaves - No info. yet.

Smallanthus uvedalia leaves
Arrow shows tapering leaf blade tissue.

Polymnia canadensis leavesPolymnia canadensis leaf (note the naked petiole).

Inflorescence - No info. yet.

Involucre - No info. yet.

Smallanthus uvedalia involucreInvolucre.

Ray flowers - 7-13 in number, pistillate with a 2-branched style exserted at anthesis; corollas 12-25 mm long. Subtended by chaffy bracts. Pappus absent.

Disk flowers - 45-80 in number, staminate. Subtended by chaffy bracts. Pappus absent.

Smallanthus uvedalia flowers

Fruits - Dark brown to nearly black when mature, inflated, glabrous. Pappus absent. Since only the ray florets are fertile, achenes are present in a ring around the circumference of the head.

Smallanthus uvedalia fruitsDeveloping achenes

Smallanthus uvedalia fruitsMature achenes

Flowering - July - September.

Habitat - Low woods, rich woods, alluvial thickets, base of bluffs.

Origin - Native to U.S.

Other info. - This showy species can be found mainly in the Ozark region of Missouri but is also found in a few counties along the Missouri river. This plant is easy to identify in the field because of its opposite leaves, which have tapering blade tissue along the petioles, and its yellow ray flowers.
This species has been called Polymnia uvedalis. Another species, Polymnia canadensis L., is similar vegetatively but has leaves which do not taper at the base. The flowers of P. canadensis have small white ray ligules also.
Smallanthus uvedalius grows easily from seed and would make a great specimen plant in cultivation.

Photographs taken in the Ozark Scenic Riverways, 8-17-03 (DETenaglia); also in Weldon Spring, 9-26-2008, and near Dutzow, MO, 9-4-2015 (SRTurner).