DESCRIPTIVE MANUAL 



303 



Chemical Composition. — The chemical composition of rib grass, 

 grown in New Hampshire, according to Kept. U. S. Dept. Agr., 

 1879, p. 121, is as follows :* 



FRESH OR AIR DRY MATERIAL.. 



Prairie Plantain (Plantago purshii R. & S.). 



Description. — A silky, green annual with slender scapes; leaves 

 linear, acute, with marginal petioles ; spikes usually cylindrical, 

 villous with rigid bracts ; flowers of two kinds on different plants ; 

 most of them cleistogamous ; sepals oblong, obtuse ; corolla lobes 

 broadly ovate ; stamens 4 ; capsule oblong, obtuse, circumscissile at 

 about the middle; seeds convex on the back, deeply concave on the 

 face. 



Distribution. — Common westward from Ontario and Illinois to 

 British Columbia, Texas and Mexico. Sometimes a troublesome 

 weed in Missouri and Nebraska. Found along railways in Iowa. 



Extermination. — This little plantain is not likely to give much 

 trouble unless the seeds are able to retain their vitality for a con- 

 siderable length of time. The plant is easily destroyed by culti- 

 vation. 



♦Jenkins and Winton. Bull. Off. Exp. Sta. 11:79. 



