GRASS FAMILY. 



5S 



12. Sporobolus airoides Torr. 



rrosfts airoides Torr. Ann. Lye. N. V. i: 151. 



Hair-grass Dropseed. 



1824. 



robolus airoides Torr. Pac. R. R. Rept. 7: Part 3 21 

 1856. 

 Culms i^-3 tall, erect, simple, smooth and gla- 



us. Sheaths generally shorter than the intcrnodes, 



ctiines sparsely ciliate at the throat ; ligule very 

 ort ; leaves smooth beneath, scabrous above and 

 imetimes sparingly hairy near the base, W~\W 

 ide at the base, attenuate into a long slender involute 

 lint, the basal about one-half as long as the culm, the 

 iperculm leaves 2 / -5 / in length; panicle 5'-i5' long, 

 ually exserted, the branches alternate or the upper 

 rticillate,, at length widely spreading, the lower 3'- 



long; spikelets }"-\" long, the scales acute, gla- 

 brous, the outer unequal, the lower one about half as 

 ng as the upper; third scale equalling the second 

 ,nd the palet. 



Prairies, Nebraska to California, south to Texas and 

 Arizona. Aug.-Sept. 



13. Sporobolus cryptandrus (Torr.) A. Gray. Sand Dropseed. (Fig. 355.) 



Azrostis cryptandra Torr. Ann. I.\ 



Sporobolus cryptandrus A. Gray, Man. 576. 1848. 



Culms i^-3^ tall, erect, simple or 

 branched at the base, smooth and glabrou*. 

 smooth, with a dense pilose ring at the summit, the 

 lower short, crowded and overlapping, the upper 

 much longer, generally enclosing the base of the pan- 

 icle; ligule a ring of short hairs; leave* 3'-6 / long. 

 i // -2 // wide, flat, glabrous beneath, scabrous above, 

 long-acuminate; panicle 6 / -io / in length, the base gen- 

 erally included in the upper sheath, rarely entirely 

 exserted, the branches spreading or ascending, alter- 

 nate, the lower i>'-3' long: spikelets i"-i \ " long, 

 the scales acute, glabrous, the outer scabrous on the 

 keel, the lower one-third as long as the upper; third 

 scale somewhat longer or shorter than the second. 



In sandy soil, coast of New Kngtand. along all th- 

 Lakes, west to Dakota, south in tli-- interior to MtMonri. 

 Texas and Mexico. Aug.-Oct. 



14. Sporobolus heterolepis A. Gray. Northern DropsetV. 



Vilfa heterolepis A. Gray, Ann. Lye. N. Y. 3: 233. 1835. 

 Sporobolus heterolepis A. Gray, Man. 576. 1848. 



Culms i-3 tall, erect, simple, smooth and glabrous. 

 Sheaths sometimes sparingly pilose at the summit, the 

 lower short, loose, and overlapping, the upper much 

 elongated and tight to the culm; ligule a ring of short 

 hairs; leaves involute-setaceous, glabrous, the margins 

 and upper part of the midrib very rough, the basal 

 about three-fourths the length of the culm, occasion- 

 ally equalling it, those of the culm shorter; panicle 

 S'-io' in length, its branches erect or ascending, al- 

 ternate or sub-verticillate, the lower \]^'-^%' long; 

 spikelets 2 // -2^ // long, the scales smooth and gla- 

 brous, the outer unequal, acuminate, the lower sub- 

 ulate, about half the length of the broad second one, 

 often awn-pointed; third scale obtuse or acute, shorter 

 than the second or occasionally equalling it. 



In dry soil, Quebec to Assiniboia, south to Pennsylvania, 

 Illinois'and Arkansas. Aug.-Sept. 



