8 WEED FLORA OF IOWA 



rye, wheat, oats, barley, corn, baffir com and millet, besides such 

 forage grasses as blue grass, timothy, brome grass, foxtail, and a 

 few ornamental plants, like pampas grass, ribbon grass, etc. 



Johnson Grass (Sorghum halepense (L.) Pers.). 



Description. — ^A stout perennial, with smooth, erect, simple 

 culms, 3-5 feet high, and strong, creeping root-stocks; leaves 

 elongated, i/4-%in. wide, acute; ligule ciliate, and on the back 

 where leaf -blade joins the sheath there is more or less pubescence ; 

 panicle open, 6-12 in. long, the whorled branches naked below, the 

 3-5-flowered racemes clustered towards their extremities; pedicels 

 of the staminate (rarely neutral) spikelets pilose with stout hairs; 

 sessile spikelet broadly lanceolate, acute, 2-3 lines long, pale green 

 or violet, becoming dark or nearly black at maturity ; callus small, 

 obtuse, shortly and sparsely barbate; first glume coriaceous, spar- 

 ingly pubescent on the flattened back, 5-7-nerved; second glume 

 similar and equaling the first, convex below, subcarinate above, 

 acute, the hyaline inflexed margins ciliate; third glume a little 

 shorter than the outer ones, membranous, faintly 2-nerved, the in- 

 folded margins ciliate ; fourth -glume broadly oval, obtuse, nearly 

 % shorter than the second, 2-lobed or bidentate at the apex, ciliate 

 awned; awn 5-8 lines long; palea a little shorter than the glumes, 

 nerveless, ciliate. Introduced and cultivated in many southern 

 states for hay; in many places it has become a dangerous weed, 

 difficult to exterminate. 



Distribution. — The weed is common in the south, often a most 

 troublesome weed. It has been reported as persisting in the 

 vicinity of Hamburg, Fremont county. 



Extermination. — ^Use the same methods as for quack grass. This 

 may become a most troublesome weed. 



Finger Grass (Digitaria sanguinalis (L.) Scop.). 



Description.— A much branched, leafy annual, 1-3 ft. high, 

 spreading on the ground, with erect, smooth, spreading culms, fre- 

 quently rooting at the lower joints, joints sometimes smooth, though 

 more frequently bearded with deflexed hairs ; sheaths loose, gener- 

 ally pilose, hairy, ciliate on the margins, with a membranaceous 

 ligule; leaves 2-4 in. long with rough margins, occasionally pilose 

 at the base; flowers produced in digitate spikes, hence the common 

 name finger grass ; spikelets less than i/g in. long in pairs, 1 nearly 

 sessile, the other with a stalk, each flower consisting of 2 sterile 



