stein. The dropseeds resemble some species of redtop (Agrostis) 

 and muhly grass (Muhlenbergia) , but are distinguishable from such 

 species by the fruit. The one-nerved, awnless, thin, shining outer 

 flower bract (lemma) is usually longer than (or at least as long as) 

 the usually unequal glumes, and loosely encloses the grain until 

 maturity, at which times the grain is allowed to fall free. In Muhl- 

 enbergia the lemma closely envelops the grain and is awned (some- 

 times only sharp-pointed). In Agrostis the glumes are nearly equal 

 and are longer than the lemma. The stalks in many species of 

 Sporobolus are solid (pithy, like cornstalks), which feature, though 

 not common for the entire genus, may aid in distinguishing those 

 species 'from redtops and many muhly grasses. Canfield 2 found that 

 74 percent of the grasses on the Jornada experimental range, in 

 southern New Mexico, where the dropseeds are well represented, have 

 solid stems and states that 



The solid stem is characteristic of the grasses which are apparently best able 

 to survive under the semiarid conditions of the Jornada region * * *. 

 Hollow stemmed grasses have not the ability to withstand the long dry periods. 



He further suggests that the solid stem may be an index as to the 

 suitability of grasses for introduction into semiarid regions. 



2 Canfield, K. H. STEM STRUCTURES OP GRASSES ON THE JORNADA EXPERIMENTAL RA.NUE. 

 Bot. Gaz. 95(4) : 636-648, illus. 1934. 



