HOW TO KNOW THE GRASSES 



55a. Spikelets 4 — 7 mm. long. 



56 



55b. Spikelets 1 — 2.5 mm. long 57 



56a. Panicle open, with spreading branches. Fig. 239. 



PRAIRIE DROPSEED Sporobolus heterolepis Gray 



Perennial; plants forming large tufts; 

 culms 30 — 70 cm. tall; panicles narrowly 

 ovoid. The spikelets become much dis- 

 tended by the ripening grain, which is 

 spherical and yellowish at maturity and 

 about 2 mm. in diameter. The pclea 

 readily splits down the middle as the grain 

 develops. Prairies. July — October. 



Figure 239 



56b. Panicle spikelike, mostly hidden in the uppermost sheath. Fig. 240. 



Sporobolus asper (Michx.) Kunth 



Perennial; tufted; culms 60 — 120 cm. tall; 

 leaf blades flat or rolled, 1 — 4 mm. wide, 

 tapering to a slender tip; panicles whitish 

 or somewhat purplish in color, 5 — 15 cm. 

 long. Open ground and prairies. August — 

 September. 



Sporoboius macer (Trin.) Hitch, is very 

 similar, but has scaly rhizomes. Pine forests; 

 Mississippi to Oklahoma and eastern Texas. 



Sporoboius clandestinus (Biehler) Hitch, is 



similar, but has hairy florets; lemma and 



palea slender-pointed, the palea longer than 



the lemma. Dry sandy lands; Connecticut to 



Figure 240 Wisconsin, Kansas, Texas and Florida. 



57a. Sheaths glabrous or nearly so at the summit. 



58 



127 



