Bean family (Fabaceae)
Description: This herbaceous perennial plant is about 6" tall, branching from the base. Initially, it produces several compound leaves from a short stem that grows only a little, after which this stem rapidly elongates and becomes up to 1' long. These elongated stems sprawl along the ground and have the capacity to root at the nodes. They are hairless and light green. The alternate compound leaves are trifoliate and hairless. They occur at intervals along the elongated stems and have long hairless petioles. The leaflets are obovate or ovate. Their margins are finely serrate. Across the upper surface of each leaflet are white markings in the form of a chevron (an upside down "V"), although for this species these markings are often degenerate, irregular, or absent. Each leaflet is about ¾" long and about half as wide. At the base of each petiole there are a pair of small lanceolate stipules that are light green and membranous; sometimes they wrap around the elongated stems. Each stipule is less than ½" in length.
Flowerheads about ¾" across are produced on long naked stalks (peduncles) that are unbranched and hairless. These flowering stalks are usually a little taller than the compound leaves. Each flowerhead has 20-50 flowers and is more or less globular in shape. Each flower is narrowly tubular, consisting of a green calyx with 5 narrow teeth and 5 petals that are white or pinkish white. When fully open, there is a small standard and 2 side petals that enclose the keel. The teeth of the calyx are equal to, or less than, the length of the calyx tube. Each flower has a very short pedicel. The blooming period occurs intermittently for several months, from late spring through the fall. The flowers gradually turn brown and are replaced by seedpods. Each little seedpod contains only a few seeds, which are flat, round or slightly heart-shaped, and variously colored. The root system consists of a shallow branching taproot and the rootlets formed by the elongated stems. This plant reproduces by seed or vegetatively, and often forms colonies.
Cultivation: The preference is full or partial sun, mesic conditions, and a soil consisting of loam or clay loam. This plant fixes nitrogen into the soil.
Range & Habitat: The non-native White Clover is a common plant that occurs in every county of Illinois. It was introduced into the United States from Europe a long time ago as a source of forage and hay. Habitats include pastures, fields, grassy meadows, lawns, parks, mowed areas along roadsides, paths through woodlands, and waste areas. This plant prefers disturbed areas that are grassy and subject to occasional mowing or grazing. In more natural areas, it is not tall enough to be very competitive with the native vegetation.
Faunal Associations: Primarily long-tongued bees visit the flowerheads to collect pollen or suck nectar, including bumblebees, honeybees, Mason bees, and Cuckoo bees (Epeoline and Nomadine). Other insect visitors include bee flies, Thick-headed flies, White butterflies, and skippers. The butterflies and skippers are not effective pollinators of clover flowers, however. Because White Clover is an important forage crop and is used in lawns, the insects feeding on the foliage or flowerheads are rather well known. The caterpillars of the butterflies Everes comyntas (Eastern Tailed-Blue), Colias cesonia (Dog-Faced Sulfur), Colias eurytheme (Orange Sulfur), and Colias philodice (Clouded Sulfur) use clovers as a food source. The White Clover is a preferred food source for the caterpillars of the Clouded Sulfur. The caterpillars of many moths feed on clovers (see Moth Table), as does Frankliniella trities (Flower Thrip). The foliage and seedheads are eaten by such upland gamebirds as the Ruffed Grouse, Greater Prairie Chicken, Wild Turkey, and Ring-Necked Pheasant. Some songbirds occasionally eat the seeds, including the Horned Lark and Smith Longspur (winter only). Various small mammals find the foliage and seedpods very attractive as a source of food, including the Cottontail Rabbit, Groundhog, Thirteen-Lined Ground Squirrel, and Meadow Vole. Large hoofed animals, such as the White-Tailed Deer, cattle, horses, and sheep, also graze on the foliage of clovers. If it is eaten in large amounts, however, White Clover can be toxic because it contains a glycoside that converts to prussic acid when the foliage is eaten by animals. However, cultivated strains of White Clover have been developed that are without this glycoside. The ecological value of White Clover to wildlife is high. It is also an important source of honey to humans.
Photographic Location: A weedy meadow at Judge Webber Park in Urbana, Illinois.
Comments: This is the familiar clover in lawns with white flowerheads. It is possible to confuse White Clover with other Trifolium spp., including the introduced Trifolium hybridum (Alsike Clover), native Trifolium reflexum (Buffalo Clover), and native Trifolium stoloniferum (Running Buffalo Clover). This latter species has never been observed in Illinois, but it can be found in neighboring Indiana. Compared to White Clover, Alsike Clover is a taller and more erect plant, with flowerheads that are usually more pink, and leaflets that are without white markings (chevrons). It doesn't form stoloniferous stems. Similarly, Buffalo Clover is a taller and more erect plant, with flowerheads that are somewhat larger in size (often 1" across or more), and leaflets that are also without chevrons. Running Buffalo Clover is even more similar in appearance to White Clover than the others because it produces long stoloniferous stems and has flowerheads that are about the same size and color. However, its leaves are also without any white markings or chevrons. Both of the native clovers also possess larger stipules (½" or longer), and they have calyx teeth that are often longer than the calyx tube.