Description:
This is
a herbaceous perennial plant with the leaves and flowers emerging
directly
from the rhizomes, and forming a basal rosette. A typical mature plant
may be 6" across and 4" high, with the flowers slightly higher than the
leaves. The leaves are individually up to 3" long and 3" across
(excluding the long petioles), and vary in color from pale green to
dark green, depending on growing conditions. They are oval-ovate to
orbicular-cordate, and crenate or serrate along the margins. The
foliage is glabrous to slightly pubescent. The flowers are about ¾"
across, and consist of 5 rounded petals. There are 2 upper petals, 2
lateral petals with white hairs (or beards) near the throat of the
flower, and a lower petal that functions as a
landing pad for visiting
insects. The flowers of this form of Viola sororia
are white to mostly white, except for violet lines radiating from the
throat of the flower (particularly the lower petal). There is no
noticeable floral scent. The blooming period occurs from mid- to late
spring and lasts about 1-1½ months. During the summer, cleistogamous
flowers without petals produce seeds, which are flung outward by
mechanical ejection from the three-parted seed capsules. The root
system consists of thick, horizontally branched rhizomes; there is a
tendency to form vegetative colonies.
Cultivation:
The preference is partial sun or light shade, and moist to mesic
conditions, although full sun is tolerated if there is sufficient
moisture. The soil should be a rich silty loam or clay loam with above
average amounts of organic matter. This plant is easy to grow, and it
will spread under favorable conditions.
Habitat & Range:
The native White Wood Violet is occasional to locally common in
Illinois;
because it is (or was) considered a mere color form of Viola
sororia, a Distribution Map is currently unavailable. Natural
habitats include open woodlands, woodland borders, savannas, and wooded
slopes along rivers or lakes. In more developed areas, it is sometimes
found in city parks, lawns, and along hedges or buildings. It is often
found in close proximity to Viola sororia sororia
(Common Blue Violet).
Faunal Associations:
The flowers have few visitors (hence the need for cleistogamous
flowers), but sometimes they attract bees and other insects. The
species Andrena viola (Violet Andrenid Bee) is an
oligolectic visitor of Viola spp. (Violets). The
caterpillars of many Fritillary butterflies feed on the foliage of
violets, including Speyeria diane (Diana), Euptoieta
claudia (Variegated Fritillary), Speyeria
aphrodite (Aphrodite Fritillary), Boloria bellona
(Meadow Fritillary), and Boloria selene myrina
(Silver-Border Fritillary). Some seeds have soft appendages that
attract ants, which help to distribute them. Various upland gamebirds
and small mammals occasionally eat the seeds, including the Wild
Turkey, Bobwhite, Mourning Dove, and White-Footed Mouse. Wild Turkeys
also eat the leaves and fleshy roots of violets. Although it is not a
preferred food source, mammalian herbivores occasionally eat the
foliage, including the White-Tailed Deer, Cottontail Rabbit, and
livestock.
Photographic
Location:
The photographs were taken of plants growing along the edge of a yard
in Urbana, Illinois.
Comments:
The White Wood Violet is the white form, f. albiflora,
of Viola sororia. The typical form of this species,
Viola sororia sororia (Common Blue Violet), which
is more common, has medium to dark violet flowers. Generally, the White
Wood Violet doesn't appear to spread as aggressively as the typical
form of this species; it is equally attractive and its light-colored
flowers are more conspicuous in shady areas. Some authorities (e.g.,
Mohlenbrock) combine the White Wood Violet with Viola sororia
priceana (Confederate Violet) and regard the two of them
together as a distinct species, Viola priceana.
However, I disagree with this taxonomic revision and prefer to regard
them as distinct color forms of Viola sororia at
the present time. This corresponds to the taxonomic classification of
the American Violet Society.