Description: This annual plant produces stems about ½–1' long that usually sprawl across the ground. It branches abundantly near the base, but very little toward the tips of the stems. The somewhat succulent stems are green or burgundy; they often have lines of white hairs. Pairs of opposite leaves occur at intervals along these stems. These leaves become larger toward the tips of the stems, spanning up to ¾" in length and ½" across. The leaves toward the base of the plant usually have short petioles that are slightly hairy, while the leaves near the tip of each stem are usually sessile. The leaves are oval-ovate, entire (toothless) along their margins, and hairless on the upper surface; the lower surface is occasionally hairy.
Individual
flowers occur from the axils of the outer pairs of leaves, while the
stems terminate in small cymes of white flowers. Each flower is about
¼" across, consisting of 5 white bifid petals (appearing to be 10
petals), 5 green sepals, 3 white styles, 2-10 stamens, and a light
green
ovary in the center. The sepals are lanceolate, hairy on the outer
surface, and longer than the petals; each sepal is at least 1/8" (3
mm.) long. The slender pedicels are finely pubescent. The
blooming period occurs during the spring for plants that are winter
annuals, and during the summer or autumn for plants that are summer
annuals. A typical plant will bloom sporadically for 1-2 months. Each
flower is replaced by a cylindrical seed capsule that is light brown
with 6 small
teeth along its upper rim; it contains several seeds. Each mature seed
is reddish brown, somewhat flattened,
and orbicular-reniform; its
surface is minutely bumpy. The root system is shallow and fibrous. This
plant spreads by reseeding itself; it can also spread vegetatively by
rooting at the leaf nodes along the stems.
Cultivation:
Typical growing conditions consist of partial or full sun, moist to
mesic conditions, and a fairly fertile loam or clay-loam soil. Light
shade and temporary flooding are tolerated.
Range & Habitat:
Common Chickweed occurs in every county of Illinois and it is quite
common. This plant is native to Eurasia. Habitats include woodland
areas prone
to flooding or standing water, thickets, cropland and fallow fields,
lawns and gardens,
nursery plots, areas adjacent to buildings, and miscellaneous waste
areas. While Common Chickweed occurs to a limited extent in natural
habitats, where it is sometimes invasive, this plant prefers areas with
a history of disturbance.
Faunal Associations:
The nectar and pollen of the flowers attract primarily small bees and
flies, including cuckoo bees (Nomada
spp.), Halictid bees, Andrenid bees, Syrphid flies, bottle
flies (Lucilia spp.),
Muscid flies, and Tachinid flies. Less common floral visitors include
nectar-seeking butterflies and parasitoid wasps (Robertson, 1929). In the absence of such
visitors, the flowers of Common Chickweed can self-pollinate. Some
insects feed on the foliage and other parts of Common Chickweed. These
species include both the adults and larvae of Cassida flaveola
(Pale Tortoise Beetle) and the larvae of such moths as Agrotis venerabilis
(Venerable Dart), Haematopis
grataria (Chickweed Geometer), and Lobocleta ossularia
(Drab Brown Wave); the Insect Table displays a more complete list of these species.
Vertebrate animals also feed on Common Chickweed and other Stellaria spp. The
seeds of such plants are eaten by the Mourning Dove, Chipping Sparrow, White-crowned Sparrow,
House Sparrow, and Field Sparrow; the Ruffed
Grouse also browses on the leaves. The Bird Table displays a more complete list of these seed-eating birds. The foliage,
flowers, and seeds are a minor source for various mammals, including
the Cottontail Rabbit, Groundhog, and White-tailed Deer (Martin et al,
1951/1961). The seeds are able to pass through the digestive tracts of
White-tailed Deer and remain viable, spreading Common Chickweed to new
areas (Myers et al, 2004). Other herbivorous mammals probably spread
the seeds in their feces as well. The Prairie Deer Mouse eats the
seeds of Common Chickweed to a minor extent (Houtcooper, 1978).
Photographic Location:
A field in Savoy, Illinois.
Comments:
This is probably the best known chickweed in Illinois, although it can
be confused with other species. Chickweed species fall into 2 large
groups: those with 3 styles (Stellaria
spp.) and those with 5 styles
(Cerastium spp.).
Like other Stellaria spp.
(Chickweeds), Common Chickweed (Stellaria
media) has only 3 styles. It differs from the
others in this genus by length of its sepals (at least 1/8"
long), which are conspicuously longer than the petals of its flowers,
and by the relatively broad shape of its leaves.
The foliage of Common Chickweed resembles Apetalous Chickweed (Stellaria
pallida) to a remarkable degree – however, the flowers of
Apetalous Chickweed lack petals and its sepals are shorter. The
blooming period of Apetalous Chickweed is restricted to the spring,
while Common Chickweed often blooms later in the year. Common Chickweed
is somewhat variable in the hairiness of its leaves, the length of its
stems, and the number of stamens in each flower.