This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual. Propagates by seeds. Time of bloom: May to September. Seed-time: July to November.
Range: New Brunswick to Alaska, southward to Florida and Texas. Habitat: Rich soil; fence rows and thickets.
A worthless weed, and sometimes a serious pest to the wool-grower, who finds the quality of his fleeces cheapened by its tiny burs.
Fig. 276. -Blue Field Madder (Sher-ardia arvensis). X 1/3.
Stems many-branched, ridged, and square, two to five feet long, very slender and too weak to support themselves, so that they clamber over other plants, clinging by means of backward-turning prickles on the stem angles. Leaves in whorls of sixes or eights, one to two inches long, narrowly spatulate, bristle-pointed, the margins and midribs rough with short, stiff hairs. Flowers very small, usually in groups of two to four in the upper axils. Corollas four-lobed, white, with four stamens inserted on the tube and two styles. Fruits small, twinned globular burs about an eighth of an inch broad, covered with short, hooked bristles. (Fig. 277.)
Since the plant is an annual, if Galium thickets are cleaned out in the spring before the first burs form, the ground must soon be rid of their presence.