Aster family (Asteraceae)
Description: This is a perennial plant about 1-3' tall that branches occasionally, often leaning toward one side. The stems are light green or reddish brown, and they have lines of white hairs. The alternate leaves are up to 4½" long and ½" across, becoming much smaller as they ascend the stems. They are narrowly lanceolate, oblanceolate, or elliptic, becoming linear near the flowerheads. There are usually a few teeth toward the tips of the larger leaves, otherwise they have smooth margins. Some hairs may be present along the major veins on the undersides of the leaves. The upper leaf surface is medium green, while the lower leaf surface is light green. The upper stems and some of the side stems produce panicles of flowerheads up to 10" long and 6" across. Each flowerhead has numerous small disk florets that are surrounded by about 8-12 ray florets. The corollas of the disk florets are initially pale yellow, but they later become brown or reddish purple; they are short-tubular in shape and 5-lobed. The petaloid rays are white and linear-oblong in shape. A typical flowerhead is about 1/3" (8 mm.) across. Each flowerhead is subtended by small green bracts (phyllaries) that are appressed together, or they are only slightly spreading.
The blooming period occurs from late summer to the fall, lasting about 1-2 months. There is little or no floral scent. The small achenes are slightly pubescent and they have small tufts of white hair. Distribution of the achenes is by wind. The root system is fibrous and rhizomatous; an older plant may develop a small caudex. Clonal offsets occasionally develop from the rhizomes. This plant occasionally forms colonies at favorable sites.
Cultivation: The preference is light shade to partial sun and moist conditions. Full sun is tolerated if the site is not too dry. Growth is best in rich organic soil, or a moisture retaining clay-loam. During dry weather, the lower leaves often wither away, and stressed out plants are vulnerable to many kinds of foliar disease.
Range & Habitat: The Calico Aster occurs in most counties of Illinois, where it is native and quite common (see Distribution Map). Habitats include moist meadows near woodlands and rivers, floodplain forests and flatwoods, woodland borders, seeps and swamps, semi-shaded sloughs near fields, and moist depressions in waste areas. This plant is primarily a woodland species, but it often strays into moist sunny areas nearby. It prefers areas with a history of disturbance.
Faunal Associations: The florets of Calico Aster have shorter nectar tubes than many other species of asters, and they seem to attract a wide variety of insects, particularly in sunny areas. More common insect visitors include short-tongued bees, wasps, and flies, and less common visitors include long-tongued bees, small butterflies, skippers, beetles, and plant bugs. These insects seek nectar primarily, although the short-tongued bees may collect pollen, while some beetles and flies feed on the pollen. Caterpillars of the butterflies, Chlosyne nycteis (Silvery Checkerspot) and Phyciodes tharos (Pearl Crescent), feed on the foliage of asters (Aster spp.), as do the caterpillars of many kinds of moths (see Moth Table). The White-Tailed Deer and Cottontail Rabbit browse on the foliage occasionally.
Photographic Location: The photographs were taken at the webmaster's wildflower garden in Urbana, Illinois.
Comments: This aster is more attractive in woodland areas, where it has a delicate appearance. It closely resembles Aster pilosus (Frost Aster), Aster ericoides (Heath Aster), and other species in the genus with small white flowerheads. The Calico Aster (Aster lateriflorus) is a somewhat lanky plant with smaller flowerheads (about 1/3" across) and fewer ray florets per flowerhead (about 10) than many similar asters (Aster spp.). In this regard, it is similar to the Heath Aster, but the latter species is a more compact plant with leaves that are shorter and more narrow than those of the Calico Aster. While the Heath Aster is often found in open prairies, the Calico Aster usually doesn't stray far from woodland and semi-shaded wetland areas. Its common name refers to the diverse colors of the disk florets as they mature. Another common name of this species is the Side-Flowering Aster, and an alternative scientific name is Symphyotrichum lateriflorum