* Outer pales narrow-lanceolate.
B. erectus: stems erect, two feet high; leaves narrow; panicle 3-5 inches long, compact, the brandies erect; spikelets not numerous; awn straight, scarcely half as long as the pale. - Fields and waste places. Fl. July.
B. asper: annual or biennial; stems 3-6 feet high; leaves long, flat, with long hairs on their sheaths; panicle loose, with long, drooping branches, bearing a few loose spikelets above an inch long; awn straight, shorter than the pale. - Hedges and thickets. Fl. July, August.
B. sterilis: annual or biennial; stems erect, 1-2 feet high; leaves softly downy; panicle six inches long or more, with numerous drooping branches, the spikelets linear-lanceolate; awns much longer than the pales. - Waste places, waysides, etc. Fl. June, July.
** Outer pales oblong, turgid.
B. arvensis: annual or biennial; stems erect, 1-3 feet high, softly downy or glabrous; panicle small, slender, elongated or compact, nearly erect, more frequently more or less drooping; pales always short, oblong or ovoid, turgid, closely packed; awn slender, usually about the length of the glumes. - Cultivated and waste places. Fl. June, July.
The following closely allied plants are included in B. arvensis by Mr. Bentham: B. secalinus: a tall cornfield variety, with a loose, more or less drooping panicle, the flowers not so closely imbricated, becoming quite distinct and spreading when in fruit.
B. mollis: common in open waste places, with a more erect panicle, either short and compact or long and slender, the whole plant softly downy.
B. racemosus: like the last, but much more glabrous.