Imágenes de páginas
PDF
EPUB

leaf blade flat, three to ten inches long, rather rough on the upper surface; panicle eliptical or oblong, branches usually spreading; spikelets three to ten inches long, seven to forty-flowered, becoming whitish when old; flowering glumes very prominently nerved and rough on the keel; emits an unpleasant odor; blooms from June to October. A weedy grass, common in fields and gardens across the continent.

Wire Grass (Poa compressa, L.).-Sometimes called English blue grass, a pale, slender, but rather rigid, perennial, with a much flattened stem, six to twenty. inches high, ascending from a more or less creeping rootstock; dense narrow panicles somewhat one-sided, one to three inches long, short branches mostly in pairs; pedicels shorter than the spikelets, which are lanceolate, five to nine-flowered and flattened; blooms from June to September. A native of Europe, but extensively naturalized in this country; found in nearly all parts of the North, growing in dry, sterile places and waste lands; an excellent forage plant, but yields less than blue grass.

Cheat or Chess (Bromus secalinus, L.).—An erect annual growing from two to three feet tall; generally smooth, occasionally pubescent at the nodes; sheath striate, usually smooth; rather broadly linear leaf blade from six to twelve inches long, smooth beneath and more or less rough or pilose on the upper surface; flowers arranged in panicles, from four to eight inches long, erect, the more or less compound branches spreading even in fruit; spikelets from six to ten lines long, and six to twelve-flowered, drooping in fruit; first empty glume three to five; second, seven-nerved; flowering glumes obscurely seven-nerved, smooth or minutely downy along the margins and near the apex, becoming cylindrical in fruit; blooms in July and August. A well-known weed of grain fields, found in all parts of the wheat-growing sections of the country.

Soft Chess (Bromus hordeaceus, L.).—An erect, usually slender, pubescent annual, growing one to three feet high, with flat leaves and contracted panicles, which are one to three inches long; the three to eight-flowered spikelets are one-half to one inch long, with pubescent glumes; flowering glumes obtuse and with awns somewhat shorter than the glumes; blooms from May to August. Introduced and found along railroads, and in the streets of cities, and in fields and waste places in the North; nearly worthless as a forage plant.

Downy Brome Grass (Bromus tectorum, L.).-A slender, erect, leafy annual seven to twenty-five inches high, with narrow, softly pubescent leaves and open, nodding panicles, three to seven inches long; spikelets each five to eight-flowered, with unequal, acuminate-pointed, hairy, empty glumes, and rough or hairy glumes, four to six lines long; awns six to eight lines long; blooming period from June to August. First introduced into the United States from Europe, and is without forage value; while not greatly troublesome in Iowa or eastward, it has become a serious pest farther west in Utah and Colorado.

Poison Darnel (Lolium temulentum, L.).-An annual with a smooth, stout stem from two to three feet tall; rough sheaths and a spike from six to twelve inches long; spikelets five to seven-flowered, the sharp-pointed empty glumes as long as the spikelets; flowering glumes turgid, awned or awnless, and both shorter and broader than in common darnel (L. perenne); blooms from June to August; also called bearded darnel. Found in waste places and cultivated grounds in the wheat-growing sections of the country and Canada.

Couch Grass or Quack Grass (Agropyron repens, (L.) Beauv.). An introduced grass already becoming troublesome in Iowa; culms one to three feet high, arising from an extensively creeping, jointed rootstock; sheaths usually smooth; leaves from four to twelve inches long,

[graphic]

Fig. 93. Quack grass or couch grass (Agropyron repens). The running "roots" (rhizomes).

smooth, scabrous or somewhat downy above; erect spikes from three to ten inches long, bearing four to eightflowered spikelets; empty glumes from five to sevennerved, sometimes notched and short-awned or acute; flowering glume nerved near the apex, awnless or shortawned. Blooming period from August to October. This grass has become naturalized on lawns and cultivated grounds and is a very common wayside pest.

Little Barley (Hordeum pusillum, Nutt.).—An annual four to ten inches tall, with stems more or less jointed at the lower nodes, the uppermost be

ing often inflated, so as to inclose the base of the spike; leaf blade from one to three inches long, usually slightly pubescent on the lower surface; spikes narrow and from one to three inches long; empty glumes rigid, the four internal glumes of each group being dilated above the base, those at the central spikelet sublanceolate, all awn-pointed; outer glumes of the imperfect, lateral spikelets bristly; flowering glumes of central spikelet awned, and florets of the lateral glumes awnless. The flowers appear from April to August. This plant has been introduced into the southern part of Iowa. Squirrel-tail Grass (Hordeum jubatum, L.).—An annual or winter annual, from six inches to two feet high with fibrous roots, forming solid bunches with leaves not unlike those of blue grass except in being paler; flowers appear in spikes two to four inches long, pale green or purplish; flowers with long awns which give it a bristly appearance; when mature, spikes break into joints; blooming period from June to August. Plant is propa

Fig. 94. Little barley (Hordeum pusillum).

[graphic]

Fig. 94a. Common wild barley (Hordeum Jubatum). (Photograph, Miss Charlotte M. King.)

« AnteriorContinuar »