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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where the species may be found. Range map of Smallanthus uvedalius. States are colored green where the species may be found.

Smallanthus uvedalius Group of plants. Photo © 2011 by David D. Taylor.

Smallanthus uvedalius Group of flowers. Photo © 2011 by David D. Taylor .

Smallanthus uvedalius Closeup of flower with bee. Photo © 2011 David D. Taylor.

Smallanthus uvedalius Closeup showing a seed and glandular hairs. Photo © 2012 David D. Taylor.

Hairy Leafcup (Smallanthus uvedalius (L.) Mack. ex Small)

By David Taylor

Hairy leafcup is a member of the Asteraceae, the Sunflower family. In older manuals and guides, this family is called the Compositae because the 'flowers' are a composite of many flowers, often of different types. Many different groups of plants fall into this family based on grouping and type of flowers. All members of the family produce one or more heads (capitulum, the term frequently used in technical keys) of flowers. Flowers in this family can be either ray flowers (these are the white 'petals' of a daisy) or disk flowers (the yellow center of a daisy). This plant produces both kinds of flowers. Twenty species are recognized in the Americas, but only one is in North America. In older manuals, hairy leafcup is called Polymnia uvedalia L.

Hairy leafcup is 0.6 to 3.0 m (24 - 118 in) tall. The stem is stout and generally smooth below the inflorescence branches. The opposite leaves form a small cup around the stem and hence the name leafcup. The leaves are palmately lobed. Leaves are green, lighter below with fine hairs scattered across the veins and both leaf surfaces. Leaves are 10 - 30 cm (4 to 12 in) long and about the same dimensions in width at the widest point. Heads are in small clusters at the end of branches. Each head has 7 to 13 yellow, 1 - 2 cm (3/8 to 3/4 in) long ray flowers to the outside, and 40-80 or so yellow tube-like disc flowers to the inside. Only the ray flowers produce seeds. Each head has overlapping bracts (phyllaries) under it which are covered with glandular hairs. A single large plant may produce one hundred or so heads. The entire plant has a resinous odor.

This leafcup is a species of moist to dry, lightly shaded to open woodland, savanna, thickets, fields, and bottomland. This species is found from Michigan southwest to Illinois, Missouri, and Kansas, south to Oklahoma and Texas, east to New York and New Jersey, and, south to Florida. Some manuals also consider it native from Mexico to Panama.

This species flowers in July to September. It is an excellent nectar/pollen plant and is visited by many species of bees and wasps.

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