This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Slender annual procumbent or diffuse herbs, with verticillate spiny-pointed leaves, and small nearly sessile pink or blue flowers, in terminal and axillary involucrate heads. Calyx-tube obovoid, its limb 4-6-lobed, the lobes lanceolate, persistent. Corolla funnelform, 4-5-lobed, the tube as long as the lobes or longer. Stamens 4 or 5, inserted on the tube of the corolla; filaments slender; anthers small, oblong, exserted. Ovary 2-celled; style 2-cleft at the summit; ovules 1 in each cavity. Fruit didymous, the carpels indehiscent. Seed erect. [Named for Dr. William Sherard, 1650-1728, patron of Dillenius.]
A monotypic genus of the Old World.
Sherardia arvensis L. Sp. Pl. 102. 1753.
Tufted, roughish, stems numerous, prostrate, ascending, or decumbent, 3'-10' long. Leaves in 4's, 5's or 6's, the upper linear or lanceolate, acute and sharp-pointed, rough-ciliate on the margins, 3"-8" long, 1 "-2" wide, the lower often obovate, mucronate; flowers in slender-peduncled involucrate heads, the involucre deeply 6-8-lobed, the lobes lanceolate, sharp-pointed; corolla-lobes spreading; fruit crowned with the 4-6 lanceolate calyx-teeth.
In waste places, Ontario to eastern Massachusetts and New Jersey. Also in Bermuda. Adventive from Europe. June-July.