GRASS FAMILY. 





9- - ' 



21. ARISTIDA L. Sp. PI. 82. 1753. 



Grasses varying greatly in habit and inflorescence. Leaves narrow, often involu 

 ceous. Spikelets narrow, i-flowered. Scales 3, narrow, the two outer carinatc the tbir-l 

 ridged and convolute, bearing three awns occasionally united at the base, the lateral awn* 

 rarely wanting or reduced to rudiments. Palet 2-ncrved. Stamen* 3. 

 Stigmas plumose. Grain free, tightly enclosed in the scale. [I. , , awn 



About loo species, in the warmer regions of tx.th heiiiisph 

 20 others occur in the southern and western parts of Nc.rth \tiuru i 



applied to all the species 



is not articulated to the scale nor united at the IM-. 

 Lateral awns usually erect not more than half as long as the h..n/..nlal or rrflrxrd central 



one, generally much shorter or occasionally wanting. 

 Third scale, exclusive of awns. 3" long or 



Central awn spiral at base, terminal straight jmrtinr. . Ai/.a 



Central awn not spiral at base, terminal straight portion * i , 



Third scale, exclusive of awns, 4" long or more. 



Central awn spiral, lateral awns one quarter to one-half as long, v A batirams* 

 Central awn not spiral or rarely so, rt flexed, lateral .mns U- M than m 



wanting. ..,* 



Lateral awns usually diverging, more than half as long as the 1. 



one, generally about equalling it. 

 First scale exceeding the second. 



Sheaths glabrous. c ^ burpuru 



Sheaths, at least the lower ones, woolly. ^ w /a Ha la. 



First scale half as long as the second or equalling it. 



First scale 5-nerved, or occasionally ;-nerved at base. >lteanika 



First scale i-nerved, sometimes with an obscure additional mi-. 

 Central awn i '2 '-4' long; panicle 4' -6' long, lax 

 Central awn i ' long or less. 



Culms simple; panicle strict, 6' -2 long. 

 Culms branched; panicle somewhat lax. not i c long. 

 \ articulated to the scale, more or less united at the K, 

 Column of the awns conspicuous, 3" long or more. 

 Column of the awns inconspicuous, less than i" long. 



, Aristida dichotoma Michx. Poverty 

 Grass. (Fig. 297.) 



Aristida dichotoma Michx. Fl. Bpr. Am. i: 41. 1803. 

 Aristida dichotoma var. CJirtissii A. Gray, Man. Kd. 6, 



640. 1890. 



Culms 6'-2 tall, erect, slender, dichotomously 

 branched, smooth or roughened. Sheaths much 

 shorter than the internodes, loose, smooth and glab- 

 rous; ligule very short, ciliate; leaves i '-3' long, less 

 than i" wide, involute, acuminate, usually scabrous; 

 spike-like racemes or panicles 2 / -5 / long, slender; 

 spikelets about 3" long ; outer scales nearly equal or 

 the lower somewhat shorter, usually awn-pointed ; 

 third scale shorter than the second, the middle awn 

 horizontal, coiled at base, the terminal straight por- 

 tion 2 // -3 // long, the lateral awns \" long or less, erect 



Dry sandy soil. Maine to Ontario. Missouri and the In- 

 dian Territory, south to Georgia and Texas. Aug.-Sept. 



2. Aristida gracilis Kll. Sk-nU-r Aristida. 

 Ig. 298.) 



Aristida gracilis\ : .\\. Hot. S C \ < 

 Arislida gracilis var. dff*i />/.. 



5, 618. 1867. 



Glabrous and smooth throughout, culms 6'-J 

 tall, erect, simple or branched. Sheaths shorter 

 than the internodes; ligule wry short . les\ 

 4' long, i" wide or less, flat, or im lry ; 



panicle spike-like, 3 '-7' long, slender; sptl 

 about 3" long; outer scales equ.^ :>wr 



somewhat shorter, awn-pointed ; third scale about 

 equalling the second, generally mottK 

 awn horizontal, the terminal straight portion 3' 

 7" in length, the lateral awn- 



Dry soil Massachusetts to Illinni* and Nebraska, 

 south to Florida and Texas. Any 



i 



