This small vine is slightly woody, forming a low mat of
leaves up to 4" tall and 1' or more across. The stems are mostly light
green to light brown and either glabrous or hairy; old stems
become brown, smooth, and woody. Pairs of opposite leaves
along these stems on short petioles up
to ¼" long. The leaves are ¼-1" long and similarly across; they are
oval to orbicular in shape and smooth to slightly undulate along their
margins. The upper leaf surface is glabrous, shiny,
mostly dark green, although it is often nearly white along the
central vein and some of the lateral veins. The lower leaf surface is
glabrous and more pale.
Pairs of upright flowers occur at the tips of branches
or from the axils of leaves. Each flower has a hairy
about ½" long, 4 stamens, and a pistil with single style. Each pair of
flowers share the same short-tubular calyx. The corolla is
trumpet-shaped with 4 spreading lobes, while the calyx is light green
with tiny teeth along its upper rim. There are 4 filiform
per style. There are two types of flowers: those with long stamens and
short styles, and those with short stamens and long styles. However,
only one type of flower can be found on any individual plant. The
blooming period occurs from late spring to mid-summer. The flowers are
fragrant. As a result of the fusion of their ovaries, each pair of
fertile flowers is replaced by a single berry. The berries
are bright red, subgloboid in
shape, and up to 1/3" (8
across. Toward the tip of each berry, there is a pair of shallow
dimples. The berry interior is fleshy and rather tasteless,
containing up to 8 seeds. The berries can persist throughout the winter
and into the spring of the following year. The root system is fibrous.
Adventitious fibrous roots can develop when the prostrate stems have
contact with moist soil.
The preference is light shade to partial sun, moist to dry-mesic
conditions, and an acidic soil containing sand or rocky material (e.g.,
sandstone). Partridge Berry is not aggressive and it can be difficult
to establish. However, it can be cultivated in a partially shaded rock
garden where the soil is shallow and competition from other plants is
restricted. Flowers and fruits are sparingly produced.
The native Partridge Berry occurs
occasionally in NE
Illinois and southern Illinois, while in the rest of the state it is
uncommon or absent. This small vine is
distributed across a wide area of eastern North America. Habitats
include rocky upland woodlands, sandy savannas, slopes of wooded sand
dunes, sandstone cliffs, sandstone ledges along ravines, mossy boulders
in wooded ravines, rocky river banks, edges of Red Maple swamps, and
bogs. Partridge Berry is found in high quality natural areas.
The flowers are cross-pollinated by
bumblebees (Hicks et
al., 1985). The
primary floral reward for these insects is nectar. Apparently very few
insects feed on the foliage of Partridge Berry. Some upland gamebirds
feed on the fruits of this vine, including such species as the Ruffed
Grouse, Bobwhite Quail, Wild Turkey, and the now extinct Passenger
Pigeon (Martin et al., 1951/1961; Bennetts, 1900; Schorger, 1955).
Mammals that feed on the fruits include the Red Fox, Eastern
Skunk, Eastern Chipmunk, White-Footed Mouse, and Woodland Deer Mouse
(Martin et al., 1951/1961; Hamilton, 1941). These animals spread the
seeds of the berries to new locations.
A shaded sandstone ledge along a
river at the
The Potholes in west-central Indiana.
This is the only species of its genus in North America. Partridge Berry
has ornamental foliage, flowers, and berries. It can distinguished from
other woody vines by its small size, pairs of showy white flowers, and
long-lasting red berries. Another common for this species is Twinberry.