This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual. Propagates by seeds. Time of bloom: May to September. Seed-time: July to November.
Fig. 229. - Field Nyctelea (Elli-sia Nyctelea). X 1/4
Range: Virginia to Ohio and Illinois, southward to Florida and Texas. Habitat: Fields and waste places.
A coarse, many-branched, and very hairy plant, untouched by grazing animals, robbing neighboring plants of much food and moisture. Stems one to three feet high, rather stout. Leaves alternate, broadly ovate to heart-shaped, three to six inches long and nearly as wide, with wavy edges and short, slightly margined petioles. Flowers in long, terminal, bractless, partly coiled spikes, which straighten as the blossoms open from the base upward; the season of bloom is so long that ripe seeds are falling from the bases of the spikes before the buds cease to unfold at the summit; corolla salver-form, violet-blue, very small, the tube longer than the hairy calyx; stamens five, included, the anthers nearly sessile. Fruit splitting into two closed carpels, ribbed on the back, each usually containing two seeds or nutlets. (Fig. 230.)
Prevent seed production by early, frequent, and persistent cutting.