Aster family (Asteraceae)
Description: This introduced perennial plant is 1-3' tall and little branched. The central stem is glabrous to slightly hairy and often angular or furrowed. A small tuft of basal leaves develops at the base of the plant, while alternate leaves occur sparingly along the central stem. These leaves are up to 5" long and ¾" across, becoming smaller as they ascend the stem. The basal and lower leaves are often oblanceolate with slender petioles, while the middle to upper leaves are more oblong and often clasp the stem. Their margins are coarsely dentate, and some of the alternate leaves are often pinnatifid toward the base. The upper and lower surface of each leaf is hairless (or nearly so). The central stem terminates in a single flowerhead on a long stalk that is nearly naked. This flowerhead spans about 1¼–2" across and has a typical daisy-like appearance. It consists of 15-35 white ray florets surrounding numerous tiny disk florets that are yellow. The receptacle of the disk florets is noticeably flattened. Each disk floret has 5 tiny lobes at its apex and is perfect, while each ray floret consists of a white oblong petal and is pistillate. At the base of the flowerhead, are several series of green floral bracts with margins that are brown and membranous. The blooming period occurs during early to mid-summer and lasts about 1½ months. Each floret is replaced by an oblongoid dark achene that has about 10 light ribs. The achenes are without tufts of hair. The root system is densely fibrous and forms offsets from short rhizomes. This plant often forms dense colonies where it is allowed to grow undisturbed.
Cultivation: The preference is full or partial sun, mesic to slightly dry conditions, and a loam or clay-loam soil. This is a reliable and rugged plant.
Range & Habitat: The Ox-Eye Daisy has naturalized in most counties of Illinois and is fairly common (see Distribution Map). It was introduced into the United States from Eurasia as an ornamental plant. Habitats include mesic to dry prairies (including old cemetery prairies), weedy meadows in wooded areas, vacant lots, areas along roads and railroads, landfills, pastures, and waste areas. This plant is usually found in degraded areas, but it also persists in higher quality habitats. The Ox-Eye Daisy is often grown in flower gardens, from which it may escape. Sometimes the rhizomes survive earth-moving operations, thereby establishing colonies of plants in new areas.
Faunal Associations: The nectar and pollen of the flowers attract a variety of insects, including small bees, flies, beetles, wasps, small butterflies, and skippers. The caterpillars of the moths Cnephasia longana (Omnivorous Leaf-Tier) and Chlorochlamys chloroleucaria (Blackberry Looper Moth) feed on the foliage. Livestock and probably other herbivores eat the foliage occasionally; the seeds can pass through the digestive tracts of these animals and remain viable. This introduces colonies of the plant into new areas.
Photographic Location: A waste area behind a rural cemetery in Champaign County, Illinois.
Comments: This is a classic example of a daisy. There are many white daisies that have been introduced from Eurasia as ornamental and herbal plants, although the Ox-Eye Daisy has larger flowerheads (more than 1¼" across). The various cultivars of Leucanthemum x superbum (Shasta Daisy) can closely resemble Ox-Eye Daisy in general appearance. The Shasta Daisy was developed by Luther Burbank from Eurasian species. Its flowerheads tend to be larger than those of the Oxeye Daisy (more than 2" across) and its leaves are less likely to be pinnatifid. In the Shasta Daisy, there is a brown membranous margin toward the apex of each floral bract, while the floral bracts of the Ox-Eye Daisy are brown along the entire length of their margins. Another scientific name for the Ox-Eye Daisy is Chrysanthemum leucanthemum.