82 AGROSTIDEAE 



importance in one particular; it never occurs on anything but 

 "g>T" soils. It is one of the few grasses that are adapted to 

 such locations and while it is a \ery poor feed it is as good as 

 the other plants that will grow on such soils and is valuable 

 at all merely because it is a little better tlian nothing. 



Sporobolus auriculatiis and 6". aspcrifoUus are two 

 species closely resembling each other, both being small low 

 grasses with small panicles and slender, sometimes weak stems 

 and rather numerous small leaves. The former is inclined to 

 form sodded patches in low spots on the dry plains in com- 

 mkI alkaline soils. The latter is more common beside 

 ditches or in the river valleys on the first flood plain above the 

 river level. Tt also is quite alkali resistant. Neither is of much 

 importance as a range or pasture grass. 



30. SPOROBOLUS R. Br. Drop Seed Grasses. 



Panicle narrow, spike-like (See also No. 10) 

 Plant tall and robust; 3 to 4 feet high. 

 Plant lower and slenderer: generally about 2 

 ft. high. 



Panicle branching and more or less spreading. 

 Plant annual; 2 to 8 inches high. 

 Plants perennial, of various sizes. 



Plants with long scaly rootstocks; the 

 empty glumes about equal. 

 Panicles about 3 inches long; stem rigifl 

 tlfough slender; leaves short; spike- 

 let slightly larger than in the next two. 



Panicles 5 to 8 inches long; stems weak 

 often elongated; leaves longer: spike- 

 let very small. 



Plants without long .scaly rootstocks; empty 

 glumes very unequal. 



Sheaths naked, or sparingly ciliate at the 

 throat. 



Plant less than 3 feet high; panicle very 

 open; empty glumes nerved. 



I'lant from 4 to 6 feet high; panicle not 

 so widely spread, with very many 

 spikelets; empty glumes without 

 nerves. 



Sheaths with a conspicuous tuft of hairs 

 at the throat. 



Sheaths pubescent; leaf blades widely 

 spreading; panicles 3 inches long or 

 less; plant not over 1 foot high and 

 slender. 



gifianteus. 



strictus. 



confusus. 



4. S. auriculatus. 



5. S. asperifoHus. 



S. airoidea. 



8. S. Wrightii. 



!>. S. NeaUeyi. 



