362 



GRASS FAMILY 



equalling or longer than the glumes, smooth or long-hairy, palet 2-nerved; 

 perennial or annual. 



1. Panicle narrow and spike-like 



a. Plants 1-2 in. high; spikelets 1 mm. long 5. Wolfii 



b. Plants 4-20 in. high 



(1) Spikelets 3-5 mm. long S . vaginiflorus 



(2) Spikelets 1.5-3 mm. long 



(a) Spikelets 1.5-2 mm. long; panicles 1-2 



cm. long S. simplex 



(b) Spikelets 2.5-3 mm. long; panicles 1-7 



cm. long S. brevifolius 



2. Panicle open, at least after flowering 



a. Lemma densely silky-hairy on the nerves ; 



spikelets 2.5-3 mm, long S\ tricholepis 



b. Lemma not densely silky-hairy 



(1) Glumes about equal 



(a) Annual; leaves 1-1.5 mm. wide S.confusus 



(b) Perennial ; leaves 2-3 mm. wide S. asperifolius 



(2) Lower glume half the length of the upper 



(a) Spikelets 4-6 mm. long 5". heterolepis 



(b) Spikelets 1.5-2.5 mm. long 



x. Panicle 1.5-3 in. long; lower glume 



about l /\ the length of the upper 5. argutus 



y. Panicle 5-15 in. long 



(x) Panicle more or less included in the 

 leaf-sheath ; spikelets 2-2.5 mm. 

 long; lower glume l /s the length 

 of the upper S. cryptdndrus 



(y) Panicle usually exserted ; spikelets 

 1.5-2 mm. long; lower glume 

 about y 2 as long as the upper S. airoides 



Stipa Linne 1753 Stipa, Spear Grass 



(Gr. sty pa, tow, probably from the use of some species) 



PI. 46, fig. 15, 16. 



Spikelets 1 -flowered, long and narrow, in open or dense panicles ; 

 glumes narrow, acute or awn-pointed ; lemma stiff, inrolled, with a hairy 

 hard point at base, bearing a usually bent awn which is spiral at base, palet 

 2-nerved, included; tall perennial or annual. 

 1. Awn 1-5 cm. long 

 a. Panicles open 



