This plant is a summer annual about ½-2½' tall that is abundantly
branched; robust specimens can be as wide as they are tall, resembling
a tumbleweed. The stems are are erect to widely spreading, terete to
angular, and pale green; young stems are covered with appressed woolly
hairs, often becoming less hairy with age. Along the stems, there are
alternate leaves 1-3" long and ¼-¾" across; they are pale green,
narrowly ovate to oblong in shape, and shallowly lobed, coarsely
toothed, or undulate along their margins. Some upper leaves may have
smooth margins. When lobes are present on the leaves, they are usually
triangular-shaped with pointed
tips. Young leaves have appressed woolly hairs on both the upper and
lower sides, although they often become less hairy with age. Leaves
are either sessile or they have short pedicels up to ½" long. During
the fall, the deciduous foliage of this plant becomes red or purple.
The upper stems terminate in either spikes or panicles of whitish green
flowers. The length of these spikes or panicles is 2-12" long; their
branches are frequently curved or crooked. Sessile flowers occur
individually along these branches and they are widely separated from
each other. Individual flowers are about 5 mm. (1/6"), consisting of 5
green sepals that curve inward, 5 stamens, and a flattened ovary with
2-3 styles. Except for its apex, the ovary of each flower is covered by
the sepals. Each sepal is lanceolate-ovate, slightly keeled in the
center, and membranous along its margins. The flowers lack petals
and there are no bracts. Flowers are sometimes pistillate; such flowers
lack stamens. The blooming period occurs from late summer into the fall
for 2-3 months. The flowers are cross-pollinated by the wind. Each
flower is replaced by a single horizontal seed that is covered by the
persistent sepals (except at the apex). Surrounding each group of
sepals and the seed, there is a pale membranous wing (wider than 0.5
mm.) that is circular and slightly fringed along its outer margin.
Individual seeds are covered with translucent membranes that are
chaffy. Individual seeds are about 1.5 mm. across, circular and
flattened in shape, black, and smooth. During the fall or winter, the
entire plant may break off at the base, becoming a tumbleweed that is
blown about by the wind. As a result, the seeds are scattered across
the landscape. The root system consists of a taproot.
The preference is full sun, mesic to dry conditions, and very sandy
soil. The size of individual plants is variable.
The native Winged Pigweed is occasional in
west-central Illinois, otherwise it is rare or absent (see Distribution
). Habitats include dry sand prairies, dry sandy savannas,
areas along major rivers, beaches and sand dunes along Lake Michigan,
sandy fields, and barren areas along railroads. This plant typically
occurs in sandy habitats with sparse ground vegetation and loose sand.
It is a pioneer species that plays a minor role in stabilizing loose
sand in wind-tossed areas.
Very little is
known specifically about floral-faunal relationships for this species.
An unidentified scale insect (Lecanium
) and an aphid (Macrosiphum
) have been observed to suck juices from the foliage.
that feed on Chenopodium
(Lamb's Quarters) undoubtedly feed on
Winged Pigweed as well. Some upland gamebirds and granivorous songbirds
probably eat the seeds, while mammalian herbivores probably feed
occasionally on the foliage. Because the small seeds of species in the
Goosefoot family can pass through the digestive tracts of both
songbirds and mammals, they may be partially distributed by these
A sandy beach along Lake Michigan
at the Indiana
Dunes State Park in NW Indiana. The photographs of the foliage were
taken during late July, while the photograph of the winged seeds was
taken during late September.
The odd-looking Winged Pigweed is the only species in its genus. It
differs from other species in the Goosefoot family (Chenopodiaceae) by
woolly hairs on its foliage and the winged membrane around its dry
fruit. In contrast, other species in this family have foliage that is
glandular-pubescent, or hairless. The flowers of Winged Pigweed occur
individually on the branches of an inflorescence, whereas most species
in the Goosefoot family have flowers that occur in clusters.