Milkwort family (Polygalaceae)
Description: This annual plant is usually unbranched and 4-12" tall. The central stem is sharply angular and hairless. The alternate or opposite leaves are sessile against the stem, ranging up to 1½" in length and 1/6" (4 mm.) across. They have a prominent mid-vein, smooth margins, and are linear or oblong-linear in shape.
The central stem terminates in a spike-like raceme of flowers. This raceme is about 1" long and ½" across. The flowers are variable in color, ranging from purplish pink, white, or green. An individual flower consists of two large sepals (i.e., the wings), three small sepals that are barely perceptible, and three small petals that form a narrow tube. One of these petals has a small crest at its tip. The wings are about 1/3" (8 mm.) long and ovate – they are the most prominent part of the flower and determine its color. The tiny tube of the petals has a similar color, but is short-lived, typically occurring near the apex of the inflorescence amid the wings. The stalk beneath the raceme has an irregular surface and spike-like remnants of the bracts where the older flowers occurred. The blooming period is from mid-summer to early fall, and lasts about 1-2 months for a colony of plants. Each flower is replaced by a capsule containing two seeds that are hairy. The root system consists of a slender taproot that has a wintergreen fragrance. This plant spreads by reseeding itself.
Cultivation: The preference is full or partial sun and moist to dry conditions. Poor soil is preferred, as this reduces competition from other plant species. This plant often grows in soil that sandy or rocky, but will thrive in loamy soil as well if it receives adequate sunlight.
Range & Distribution: The native Field Milkwort occurs occasionally in most counties of Illinois. It is the most common Polygala spp. (Milkwort species) in the state. Habitats include moist to dry prairies, sand prairies, typical savannas and sandy savannas, woodland edges, glades, and abandoned fields.
Faunal Associations: The nectar of the flowers attracts small to medium-sized long-tongued bees, short-tongue bees, and bee flies. Among the bees, are such visitors as Dagger bees, Miner bees, and Cuckoo bees. Little information is available about the food value of the Milkworts to birds and animals.
Photographic Location: A moist sand prairie at Hooper Branch Savanna Nature Preserve in Iroquois County, Illinois. The location was flooded earlier in the year, which is why the leaves have a muddy appearance.
Comments: As a group, the Milkworts have not received as much attention as they deserve. Some species, such as this one, have fairly attractive flowers. They are usually found in locations with acid sandy soil, but some species prefer dry sites with rocky material or loess. The Polygala spp. can be distinguished from each other by taking into consideration the following: 1) whether the leaves are alternate or whorled, 2) the shape, size, and color of the wings on the flowers, 3) the density of flowers on the spike or spike-like raceme, and 4) the conspicuousness of the tubular petals. The slender leaves of Field Milkwort are usually alternate, rather than whorled. This species has fairly large wings (about 1/3" or 8 mm.) that are ovate in shape. They are often purplish pink, but may turn white near the base. The density of flowers on the spike-like raceme is high, while the tubular petals are inconspicuous. Field Milkwort has a wide distribution in the Eastern United States, and different varieties have been described.