Annual or perennial grasses, with flat or involute leaf-blades and terminal spikes. Spike-lets 3-many-flowered, sessile, single and alternate at each notch of the usually continuous rachis, the side of the spikelet turned toward the rachis. Two lower scales empty; flowering scales rigid, rounded on the back, 5-7-nerved, usually acute or awned at the apex; palets 2-keeled, the keels often ciliate. Stamens 3. Styles very short, distinct. Stigmas plumose. Grain pubescent at the apex, usually adherent to the palet. [Greek, referring to the growth of these grasses in wheat fields.]

About so species, in all temperate regions. Type species: Agropyron cristatum J. Gaertn.

Culms not densely tufted; plants with creeping rootstocks or stolons.

Spikelets glabrous or hispidulous.

Empty scales strongly 5-11 -nerved.

Empty scales attenuate into an awn or awn-point; plant green.

Under surface of the leaf-blades smooth, the upper surface often pubescent; an

introduced weed.

1.

A. repens.

Under surface of leaf-blades very rough, the upper surface glabrous; a western grass.

2.

A. pseudorepensr.

Empty scales rather abruptly narrowed to a blunt point; plant glaucous.

3.

A. pungens.

Empty scales usually faintly 1-3-nerved, sometimes 5-nerved.

4.

A. Smithii.

Spikelets densely pubescent.

5.

A. dasystachyum.

Culms densely tufted; plants with no rootstocks or stolons.

Awn shorter than the flowering scale.

Empty scales broad above the middle.

6.

A. biflorum.

Empty scales narrowed from below the middle.

7.

A. tenerum.

Awn much longer than the flowering scale.

8.

A. caninum.

1. Agropyron Repens (L.) Beauv. Couch-Grass. Quitch-Grass

Fig. 686

Triticum repens L. Sp. PI. 86. 1753. Agropyron repens Beauv. Agrost. 146. 1812.

Culms 1 -4 tall, from a long jointed running root-stock. Sheaths usually shorter than the internodes, smooth and glabrous; ligule very short; blades 3'-12' long, 1"-5" wide, smooth beneath, rough above; spike 2'-8' in length, strict; spikelets 3-7-flowered; empty scales strongly 5-7-nerved, usually acute or awn-pointed, sometimes obtuse; flowering scales smooth and glabrous, acute or short-awned at the apex.

In fields and waste places, almost throughout North America except the extreme north. Naturalized from Europe and often a troublesome weed. Very variable. Native also of Asia. Quitch-, Twitch-, or Witch-grass. Stroil. Quichens. Squitch. Wickens. Shelly-, Knot-, Dog-, Shear- or Quack-grass. Blue-joint. Slough- or Pond-grass. False Wheat. Colorado blue-grass. July-Sept.

1 Agropyron Repens L Beauv Couch Grass Quitch Gras 6861 Agropyron Repens L Beauv Couch Grass Quitch Gras 687