This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Perennial. Propagates by seeds. Time of bloom: June to August.
Seed-time: July to September.
Range: Wisconsin to the Plains of the Saskatchewan, southward to Missouri and New Mexico. Habitat: Prairies; dry fields and meadows.
A troublesome, persistent weed, difficult to suppress, which is appearing locally in some of the Eastern States, traveling by the agencies of grass seeds or baled hay. Grazing animals reject it when growing because of the copious, bitter, and milky juice; and when dried in hay its stems are too hard and woody to be eaten.
It has a thick, deep-boring, woody root, from which several tufted stems arise, eight to eighteen inches high, erect, stiff, branching, round, and finely grooved. Lower leaves a half-inch to two inches in length, narrowly lance-shaped to linear, the upper ones becoming much smaller, until near the top they are mere awllike scales. Heads erect, solitary and terminal, about a half-inch broad, usually five-flowered, the rays five-toothed at the tips, rosy pink or light purple; involucre about a half-inch high, cylindric, with an inner row of five to eight linear bracts, scarious-margined, united at the base, and surrounded by several very short outer ones. Achenes very slender, nearly a quarter-inch long, round, tapering, truncate at summit, with a copious, light brown pappus by which they are freely wind-distributed. (Fig. 379.)
Prevent seed development and distribution by early and repeated cutting. Infested grass lands should be harvested before the first flowers mature, and should later be broken up for a cultivated cleansing crop before reseeding. For newly infested areas the labor of hand-pulling is not too great a price to pay in order to save clean ground from being fouled with a growth so pernicious.
Fig. 379. - Rush-like Lygodesmia (Lygodesmia juncea). X 1/6.