DESCRIPTIONS OF SOME COMMON WEEDS 139 



sheaths. Common in moist, sandy soil and fields, and 

 along railways. 



Grass Family (Gramineae). Fibrous-rooted annuals or 

 perennials, rarely woody, with hollow stem ; alternate, 

 two-ranked leaves ; sheaths split or open on the side op- 

 posite the blade ; flowers consisting of two-ranked glumes, 

 forming a one to many-flowered spikelet; flowering 

 glumes inclosing a small bract called the palet; stamens 

 one to six, usually three ; anthers versatile, two-celled ; 

 stigmas hairy. A large family of about 3,500 species, many 

 of which, such as wheat, corn, oats, and wild rice, are very 

 important to man. Sorghum and sugar cane, which fur- 

 nish the sugar of commerce, also belong to this family. 



Johnson Grass (Sorghum halapense, (L.) Pers.). An 

 erect, stout perennial three to five feet tall, with simple, 

 smooth stem, and strong creeping rootstocks ; leaves 

 elongated, acute, and, where the leaf-blade joins the 

 sheath, the back is more or less pubescent; open panicle 

 six to twelve inches long, the whorled branches being 

 naked below, with three to five-flowered racemes clus- 

 tered near their extremities ; pedicels of the staminate or 

 neutral spikelets armed with stout hairs, the sessile spike- 

 let broadly lanceolate, acute, pale green or violet, becom- 

 ing dark or nearly black at maturity; first glume five to 

 seven-nerved, second glume similar and equaling the 

 first, third shorter, outer ones faintly two-nerved and the 

 fourth two-lobed, awned, ciliate, one-half as long as the 

 second; blooming period all summer. This plant has 

 been introduced and cultivated in many parts of the 

 southern states for hay, but has become, in various sec- 

 tions, a dangerous weed and is difficult to exterminate. 



Smooth Crab Grass (Digitaria humifusa, Pers.). An 

 annual from six inches to two feet tall, closely resembling 

 finger grass (D. sanguinalis), in habit, but is smooth 

 throughout excepting for a few hairs at the throat of the 

 sheath ; spikes two to six, widely diverging and smaller 



