mewhat V-shaped, roughened crosswise by
prominent fine more or less branching ridges; ridges of palea on concave
side less prominent. Introduced from Europe. Very common in hoed annual
crops.

[Illustration: Fig. 24.]

=Green Foxtail. Green Pigeon Grass.= _Setaria viridis_ (L.) Beauv.
_Chaetochloa viridis_ (L.) Nash. Spikelets, light to dark brown mottled,
2-2.3 mm. long, after threshing or much rubbing consisting of the grain
and two firm coverings, the rounded one known as a floral glume which
covers the edges of the flattened side, oval, the surface granular and
very faintly striate, lengthwise and ridged crosswise. Much resembling
Hungarian grass. Introduced from Europe. Found with yellow foxtail.

[Illustration: Fig. 25.]

=Porcupine Grass.= _Stipa spartea_ Trin. Grain inclosed in the floral
glume, light brown, 18 mm. long, clothed on the lower half with short
brown hairs slanting upward, bearing at the base a sharp, hard, curved
beak, when dry the attached awn is twisted for 6 cm. and straight and
bent at right angles about 6 cm. When moistened, the awn untwists more
or less; twisting and untwisting the beards hold what the beak pierces,
thus making it a formidable weapon to enter the skins of sheep, goats
and dogs. Fortunately it is seldom abundant. Sandy land Michigan and
westward.

SEDGE FAMILY. CYPERACEAE.

[Illustration: Fig. 26.]

=Yellow Nut-Grass.= _Cyperus esculentus_ L. This is a species of sedge,
and so far as I have examined, produces no seeds, perhaps having lost
that method of reproduction, as it acquired the habit of spreading by
tubers here illustrated. In moist soil, sometimes a troublesome weed.

[Illustration: Fig. 27.]

=Ovoid Spike-rush.= _Eleocharis ovata_ (Roth.) R. & S. Spike ovoid, 4-10
mm. long, achene pale to chestnut brown, shining, obovate-oblong,
compressed, about 1 mm. long, bearing a triangular tubercle at the apex,
and six to eight barbed bristles, 1.3-1.7 mm. long, very variable. Not
troublesome except in low land.

RUSH FAMILY. JUNACEAE.

[Illustration: Fig. 28.]

=Slender Rush.= _Juncus tenuis_ Willd. Seeds light brown to amber color,
translucent, flattened, oval, half oval, oblong, ovoid, the acute apex
curved to one side, about 0.3 mm. long. Dry to moist soil, almost
throughout North America, now migrating to all parts of the world. A
very common, grass-like rush in this state, seldom recognized by any one
under any name, except by a first-rate botanist.