Annual herb 7 - 40 cm tall Stem: erect, unbranched or brached near top. Leaves: alternate, 1 - 4 cm long, about 1.5 mm wide, linear to narrow elliptic or narrow lance-shaped with a very short pointed tip. Inflorescence: a dense cluster (raceme), 1 - 2 cm long, 0.6 - 1.4 cm across, spherical or cylindric and rounded at the tip. Flowers: rose purple to white or greenish, with three small outer sepals and two petal-like inner sepals (wings) 3 - 6.3 mm long and 2.5 - 3.5 mm wide. The three petals are fused into a tube about half the length of the egg-shaped wings, and one petal is fringed. Fruit: a dehiscent capsule. The pear-shaped seeds are attached to an appendage (aril) with two linear lobes about three-fourths the length of the seed (1 - 1.3 mm).
Similar species: Polygala sanguinea, Polygala polygama, Polygala incarnata, Polygala paucifolia, and Polygala senega all have alternate leaves. Polygala paucifolia is a creeping perennial with flowers longer than 11 mm. Polygala polygama and Polygala senega each have clusters of several stems. Polygala incarnata has leaves that tend to fall off by flowering time.
Flowering: late May to early October
Habitat and ecology: Sterile sandy open areas, dry prairies, and non-sandy sterile abandoned fields throughout the Chicago Region, and in sandy acid flats in the eastern part of the region.
Occurence in the Chicago region: native
Etymology: Polygala comes from the Greek words polys, meaning much, and gala meaning milk, referring to the old belief that milkworts would aid in milk secretion. Sanguinea means blood-red.
Author: The Morton Arboretum
From Flora of Indiana (1940) by Charles C. Deam
This species has three color forms, purple, white, and intermediate. Linnaeus described the first as Polygala sanguinea and the last as Polygala viridescens. The last named plant is now regarded as a form of Polygala sanguinea. The white form has also been named but has not been found in Indiana. Our plants vary from almost white to purplish but most of them are more or less of a deep rose color. This species is found in poor and slightly acid soil of old fallow fields, of open wooded slopes, of the borders of marshes, in suitable habitats along roads and railroads, and in sandy wheat stubble fields. It is usually infrequent and much scattered but I once saw it as a common plant in a moist wheat stubble field in Jasper County.
Erect annual 1-4 dm, simple or branched above; lvs linear or narrowly elliptic, 1-4 cm נ1.5 mm; racemes sessile or short-peduncled, very dense, head-like, rounded or short-cylindric, 1 cm thick, the floriferous portion 1-2 cm, the whole axis to 4 cm; fls rose-purple, white, or greenish; wings oval, 3-5 mm, or longer in fr, blunt, with conspicuous midvein; cor half as long as the wings; seed pyriform, the 2 linear lobes of the aril extending beyond the middle. Fields, meadows, and open woods; N.S. to Minn., s. to S.C. and La. July-Sept. (P. viridescens)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.