618 GRAMINE^:. (GRASS FAMILY.) 



stout (l-3 high) ; panicle contracted; palets linear, |'- 1' long (including the 

 long callus), pubescent below, shorter than the lanceolate slender subulate-pointed 

 greenish glumes; the twisted strong awn (3'-7' long, pubescent below, rough 

 above. (S. juncea, Pursh?) Plains and prairies, from Illinois and N. Michi- 

 gan northwestward. May -July. 



16. ABISTIDA, L. TRIPLE-AWNED GRASS. (PI. 8.) 



Glumes unequal, often bristle-pointed. Lower palet tipped with three awns ; 

 the upper much smaller. Otherwise much as in Stipa. Culms branching: 

 leaves narrow, often involute. Spikelets in simple or panicled racemes or spikes. 

 Grain linear. (Name from arista, a beard or awn.) All grow in sterile, dry 

 soil, and all ours have the awns naked and persistent, and flower late. 



* Awns separate to the base, not jointed with the palet. 



*- Awns very unequal ; the much shorter or minute lateral ones erect ; the elongated 

 middle one horizontal or turned downwards : glumes equal or the upper one longer : 

 low (5'- 18' high] and branching, mostly tufted annuals. 



** Spikelets few in loose simple spikes or racemes: glumes 3 5-nerved. 



1. A. ramosissima, Engelm. mss. Culms diffusely much branched; 

 glumes (9" -10" long) rather shorter than the flower; middle awn 1' long, 

 soon abruptly hooked-recurved, the lateral ones hardly 2" long ; ligule truncate, 

 bearded. Dry prairies of Illinois (Engelmann, Vasey) and Kentucky (Michanx). 

 Var. UNIARISTATA, with lateral awns wanting. Odin, S. Illinois, Vasey. 



-* *- Spikelets more numerous : glumes (3" -4" long) carinately l-nerved. 



2. A. dichdtoma, Michx. (POVERTY GRASS.) Culms low, much 

 branched throughout, ascending ; Spikelets in short narrow clusters ; glumes 

 nearly equal, longer than the flower, fully equalling its minute lateral awns, the 

 soon reflexed middle awn about the length of the palet. Dry, sandy or gravelly 

 fields : common, especially southward. 



3. A. gracilis, Ell. Culms slender, erect (6' -18' high), naked above and 

 terminating in a slender raceme- or spike-like virgate panicle ; glumes about 

 the length of the flower, the exserted lateral awns varying from one third to fully 

 half the length of the horizontally bent middle one; or in var. DEPAUPERATA, from 

 one fifth to one third its length. Sandy soil, coast of Mass, and from Illi- 

 nois southward. Middle awn 6" -9" long, in the ordinary forms. In the var. 

 which abounds on micaceous hills near Philadelphia (C. E. Smith), the flowers 

 are much smaller, and awns shorter ; but it passes into the larger form. 



-i -t Awns all diverging and alike, or the lateral ones moderately shorter. 

 ** Glumes equal or the upper one longer. 



4. A. Stricta, Michx. Culms (2 -3 high) densely tufted from a perennial 

 root, bearing a (1) long spiked panicle,' leaves involute-thread-form, long, rigid, 

 sometimes downy: awns about the length of the flower (6") or the lateral one 

 third shorter. Virginia and southward. 



5. A. Oligantha, Michx. Culms (6" -20" high) tufted from an annual? 

 root, bearing a.loosely few-flowered raceme; leaves short, somewhat involute when 

 dry; lower glume 3-5-nerved (nearly V long); awns capillary, 1^-3' long, 

 much exceeding the slender flower. Virginia to Illinois, and common south- 

 westward. 



