This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Crepis capillaris, Wallr. (Crepis virens, L.)
Introduced. Annual or biennial. Propagates by seeds.
Time of bloom: July to September.
Seed-time: August to October.
Range: Atlantic States from New York southward; also on the Pacific Coast. Habitat: Fields and waste places.
Hawksbeards are European weeds, not as yet very widely distributed in this country but noted in their range as "becoming frequent." This species has a stem ten to thirty inches tall, smooth, slender, branching at the top into a loose, corymbose flower-cluster. Basal leaves somewhat resembling those of a Dandelion, five to eight inches long, lance-shaped to spatulate, pinnatifid or merely coarsely toothed, narrowing to winged petioles; stem leaves much smaller, long-pointed, clasping the stem with an auriculate base, the upper ones usually entire. Heads numerous, on very slender peduncles, about a half-inch broad, gold-yellow; involucre cylindric, of one row of equal bracts. Achenes tapering at both ends, ten-ribbed, smooth, without a beak, the pappus a soft, thick, white aigrette attached to the apex. (Fig. 381.)
Fig. 381. -Smooth Hawks-beard (Crepis capillaris). X 1/4.
Prevent seed development. Crowns of autumn plants should be hoe-cut or spudded from their roots, and flower-stalks should be cut in their first bloom. In cultivated ground the necessary tillage will keep the weed suppressed, but plants along roadsides and in waste places should not be allowed to mature fruit to the injury of neighboring land.