Description:Thisannual plant produces stems about ½–1' long that usuallysprawl across the ground. It branches abundantly near the base, butvery little toward the tips of the stems. The somewhat succulent stemsare green or burgundy; they often have lines of white hairs. Pairs ofopposite leaves occur at intervals along these stems. These leavesbecome larger toward the tips of the stems, spanning up to ¾" in lengthand ½" across. The leaves toward the base of the plant usually haveshortpetioles that are slightly hairy, while the leaves near the tip of eachstem are usually sessile. The leaves are oval-ovate, entire (toothless)along their margins, and hairless on the upper surface; the lowersurfaceis occasionally hairy.
Individualflowers occur from the axils of the outer pairs of leaves, while thestems terminate in small cymes of white flowers. Each flower is about¼" across, consisting of 5 white bifid petals (appearing to be 10petals), 5 green sepals, 3 white styles, 2-10 stamens, and a lightgreenovary in the center. The sepals are lanceolate, hairy on the outersurface, and longer than the petals; each sepal is at least 1/8" (3mm.) long. The slender pedicels are finely pubescent. Theblooming period occurs during the spring for plants that are winterannuals, and during the summer or autumn for plants that are summerannuals. A typical plant will bloom sporadically for 1-2 months. Eachflower is replaced by a cylindrical seed capsule that is light brownwith 6 smallteeth along its upper rim; it contains several seeds. Each mature seedis reddish brown, somewhat flattened,and orbicular-reniform; itssurface is minutely bumpy. The root system is shallow and fibrous. Thisplant spreads by reseeding itself; it can also spread vegetatively byrooting at the leaf nodes along the stems.
Cultivation:Typical growing conditions consist of partial or full sun, moist tomesic conditions, and a fairly fertile loam or clay-loam soil. Lightshade and temporary flooding are tolerated.
Range & Habitat:Common Chickweed occurs in every county of Illinois and it is quitecommon. This plant is native to Eurasia. Habitats include woodlandareas proneto flooding or standing water, thickets, cropland and fallow fields,lawns and gardens,nursery plots, areas adjacent to buildings, and miscellaneous wasteareas. While Common Chickweed occurs to a limited extent in naturalhabitats, where it is sometimes invasive, this plant prefers areas witha history of disturbance.
Faunal Associations:The nectar and pollen of the flowers attract primarily small bees andflies, including cuckoo bees (Nomadaspp.), Halictid bees, Andrenid bees, Syrphid flies, bottleflies (Lucilia spp.),Muscid flies, and Tachinid flies. Less common floral visitors includenectar-seeking butterflies and parasitoid wasps (Robertson, 1929). In the absence of suchvisitors, the flowers of Common Chickweed can self-pollinate. Someinsects feed on the foliage and other parts of Common Chickweed. Thesespecies include both the adults and larvae of Cassida flaveola(Pale Tortoise Beetle) and the larvae of such moths as Agrotis venerabilis(Venerable Dart), Haematopisgrataria (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. Theseeds of such plants are eaten by the Mourning Dove, Chipping Sparrow, White-crowned Sparrow,House Sparrow, and Field Sparrow; the RuffedGrouse 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, includingthe Cottontail Rabbit, Groundhog, and White-tailed Deer (Martin et al,1951/1961). The seeds are able to pass through the digestive tracts ofWhite-tailed Deer and remain viable, spreading Common Chickweed to newareas (Myers et al, 2004). Other herbivorous mammals probably spreadthe seeds in their feces as well. The Prairie Deer Mouse eats theseeds 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 canbe confused with other species. Chickweed species fall into 2 largegroups: those with 3 styles (Stellariaspp.) and those with 5 styles(Cerastium spp.).Like other Stellaria spp.(Chickweeds), Common Chickweed (Stellariamedia) has only 3 styles. It differs from theothers 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 (Stellariapallida) to a remarkable degree – however, the flowers ofApetalous Chickweed lack petals and its sepals are shorter. Theblooming period of Apetalous Chickweed is restricted to the spring,while Common Chickweed often blooms later in the year. Common Chickweedis somewhat variable in the hairiness of its leaves, the length of itsstems, and the number of stamens in each flower.
