488 Key to the System of 



FENTAFOGON. 



2060. Middle awn slightly twisted. 



Seldom tall; leaves short, principally basal, mostly quite 

 narrow, gradually pointed, often beset with hairlets ; 

 panicle contracted ; spikelets rather large ; outer bracts 

 of almost equal length, pointed ; rhacheolar stalklet of 

 flower very short, silklike-invested ; middle awn seldom 

 very long ; fruit loose within its bracts. 



F. Billardieri. 



ANXSOFOGON. 



2061. Spikelets few or several, hardly paniculated. 



Often tall ; leaves much elongated, longitudinally involute, 

 gradually pointed ; spikelets on thin mostly elongated 

 stalks, drooping ; rhacheole very short ; outer bracts very 

 long, but proportionately narrow, membranous, gradually 

 much pointed ; fruit-supporting bract outside imperfectly 

 beset with short soft hairlets ; fruit-covering bract firm ; 

 anthers long, but quite narrow ; styles about as long as 

 the stigmas ; fruit beset with minute hairlets at and 

 toward the summit. A. avenaceus. 



AZIISTZDA. 



2062. Awn three-branched from far above its base. 



Desert-plant, rather tall, occasionally dwarfed ; leaves 

 through longitudinal involution almost filiform, much 

 pointed ; panicle contracted and usually somewhat 

 twisted j outer bracts longer than the inner, generally 

 of a purplish hue, much pointed, the lowest shorter than 

 the other ; stalklet very short, producing hairlets at the 

 summit ; awn very long, its undivided portion thinly 

 filiform, but spirally twisted, jointed at the base, its 

 divisions slightly rough ; fruit loose within its bracts, 

 narrow. A. arenaria. 



Awn three-branched from its base ... ... ... 2063 



2063. Branches of the panicle very much elongated, with 



spikelets towards the summit only. 



Desert-plant, rather tall : leaves long and narrow, much 

 pointed; panicle elongated, distantly branched ; spikelets 

 on very long and thin stalks ; outer bracts of unequal 

 length ; awn rather long, without any torsion ; fruit nar- 

 row, loose within its bracts, comparatively long. 



A. leptopoda. 



Branches of the panicle short ... ... .... 2064 



