478 Key to the System of 



LEPTURUS. 



2020. Spike often curved. 



A coast-grass, never tall ; stems slender, generally ascend- 

 ing ; leaves short, quite narrow, soon incurved along the 

 margin ; stalk of the upper leaves turgid ; lowest bracts 

 two, pointed, the outer five-streaked, t. incurvatus. 



Spike often straight. 



A coast-grass, usually dwarf and ascending ; leaves rather 

 narrow, never long ; lowest bract one, pointed, five- 

 streaked. L. cylindricus. 



PAPFOPXORUM. 



2021. Fruit-supporting bracts terminated each by nine very 



short setular awns. 



Seldom tall ; leaves moderately long ; spike-like panicle 

 short, somewhat cylindrical, from pale-greenish varying 

 to dark-colored ; outer bracts longitudinally several- or 

 many-streaked, surrounded and partly invested by soft 

 hairlets ; undivided portion of the fruit-supporting bract 

 very short. P. commune. 



ERXANTHUS. 



2022. Spike-like panicles usually two or three, jointly ter- 



minal, brownish from dense vestiture. 

 Desert-grass, often tall ; leaves rather narrow, much 

 pointed ; panicular or racemous spikes occasionally in- 

 creased to five or diminished to one ; awn quite short. 



E. fulvus. 



ANDROPOGON, 



2023. Spikes of spikelets terminating the stem 2024 



Spikes of spikelets paired in a contracted panicle or 

 most of the spikelets ternately dispersed in an ample 

 panicle ... 2027 



2024. Outer bract always with an impression towards the 



middle. 



Nodes glabrous ; leaves narrow, much pointed, the stem- 

 leaves never long ; spikes from two to five, without any 

 floral leaves ; outer bract elliptical, longitudinally venular- 

 streaked, beset with soft shining hairlets ; last inner bract 

 provided with a long twisted awn. A. pertusus. 



Outer bract usually without any impression ... 2025 



