490 Key to the System of 



Membrane at the inner base of the leaves abbreviated 2069 



2069. Outer bracts colorless. 



Coast-plant, tall and quite straight; leaves very long, 

 filiform-cylindrical, very rigid, pungent, often light-green ; 

 panicle long, much contracted, somewhat twisted ; outer 

 bracts elongated, much pointed ; fruit-supporting bract 

 beset with short but spreading somewhat deciduous 

 indument ; awn moderately long, capillary, flexuous, 

 glabrous ; fruit loose within its bract. S. teretifolia. 



Outer bracts yellowish. 



Often tall ; leaves mostly long, almost filiform from marginal 

 involution ; panicle elongated, rather contracted, its 

 branches often short ; spikelets rather large ; outer bracts 

 much pointed, inner bracts somewhat shorter ; awn long, 

 only slightly invested with very short hairlets or almost 

 glabrous ; fruit loose within its bracts. S. flavescens. 



2070. Outer bracts at their summit somewhat truncated 



and denticulated. 



Tall ; leaves long, narrow, involute along the margin ; 

 panicle elongated, somewhat spreading; spikelets large, 

 blunt at the base ; awn long, usually invested with very 

 short hairlets along its lower portion ; fruit loose within 

 its bracts. S. pubesceus. 



Outer bracts much pointed ... .. ... ... 2071 



2071. Awn at least to the middle beset with hairlets. 



Generally tall ; leaves long, narrow, often marginally in- 

 flexed ; panicle long, somewhat contracted, its branches 

 almost glabrous ; spikelets large ; outer bracts gradually 

 pointed, much exceeding the inner bracts ; awn very long, 

 its vestiture conspicuous ; fruit loose within its bracts. 



S. semibarbata. 



Awn glabrous... ... ... ... ... ... 2072 



2072. Outer bracts ending in three points, the two lateral 



short. 



Desert-plant, often tall ; leaves long, often involute along 

 the margin ; panicle elongated, moderately spreading ; 

 spikelets rather large ; middle point of outer bracts the 

 longest ; fruit-supporting bract turgid, its vestiture 

 greyish, appressed and shining; awn rather long, twisted, 

 slightly rough ; fruit loose within its bracts. 



S. aristiglumis. 



