Wild quinine (Parthenium integrifolium) of the Aster, Sunflower or Composite (Asteraceae) family is an herbaceous perennial with frosty composite flowerheads. The genus name is from the Greek word parthenos, for virgin––only the pistillate ray florets are fertile. The specific epithet, from Latin, means “entire-leaved,” meaning undivided, although the leaf margins are crenate to serrate-dentate. The common name is based on use of the plant as a substitute for quinine (derived from Cinchona trees of South America) to treat malaria during World War I. It is also called American feverfew. In the U.S., wild quinine occurs from northeast Texas to southern Minnesota, east to the Atlantic Coast. In Arkansas, plants occur primarily throughout in the Interior Highlands and Arkansas River Valley, with localized occurrences in areas of the West Gulf Coastal Plain and Mississippi Alluvial Plain. Habitat is widely varied, with a preference for mesic to dry, sunny sites with well drained soils, found in prairies, glades and woodland edges.
Plants are taprooted with fibrous rootlets, along with rhizomes, that produce off-set plants. The root crown of mature plants has several growth points which produce single stems surrounded by basal leaves. Mature stems are erect and stout, typically unbranched below the inflorescence. Plants continue to grow to the time of fruiting with a final height of 2 to 3 feet. Leaves disintegrate over winter, but dead stems may still remain in spring.
Wild quinine is a leafy plant, both with numerous basal leaves and with widely spaced cauline leaves (to 10+ inches apart). Leaves are steeply ascending, dark green above and lighter beneath. Leaf margins are boldly toothed (crenate-dentate to serrate) and crinkly. The blades are covered above and below by very short hispid pubescence and feel slightly fuzzy to the touch.
The inflorescence, visible after stems emerge in late winter and blooming from mid-spring to mid-summer, consists of flat-topped corymbose groups of heads (to 8 inches across) which terminate the stems. Flowerheads are ¼ to 1/3 inch broad.
Flowerheads first appear fuzzy and greenish white from an expanding, pale green, cup-shaped involucre. Involucres comprise five to six densely pubescent, broadly triangular, clasping, stubby phyllaries (bracts). Heads have 20 to 35 closely spaced, staminate disk florets and five (occasionally six) well-spaced, pistillate ray florets, separated by several disk florets. Whitish, tubular, finely pubescent disk florets, in bud, have a flattened, frosty-looking apex. As disk corollas open, five very short triangular lobes flare widely and a column of black connate anthers emerges. The whitish, pistillate (no stamens) ray florets have a stubby, two-lobed ligule with a short tubular base, attached to an inferior ovary. Ray florets reach anthesis before the staminate disk florets disperse their white pollen. Involucres remain clasping through fruiting.
In mid to late summer, flowerheads become brown and slowly disintegrate. Each ray floret produces a single black, shield-shaped, one-seeded achene topped with two or three slender awns.
For a garden area, wild quinine would add strong structure and seasonal interest from spring into late summer. It has attractive leaves and a long blooming period. Due to its potential to form colonies in some habitats, it may be better suited for a sunny natural area. Degree of spread by seed is not known, but seed heads can be easily removed. It provides nectar and pollen to various bees, flies and wasps.
Wild quinine in Arkansas is sometimes recognized as consisting of two varieties, or even two species by some authorities. Variety hispidum is strongly rhizomatous and has a denser stem and leaf pubescence of short, stiff (hispid) hairs than variety integrifolium. The only other species of the genus in Arkansas is the non-native Santa Maria feverfew (Parthenium hysterophorus) which has been documented in a few scattered counties. This species is annual, has smaller flowerheads, and has large leaves that are highly dissected.
Article and photographs by ANPS member Sid Vogelpohl