GRAMINEAE (GRASS FAMILY) 



125 



84. A. dichotoma. 

 Spikelet x 2%. 



erect teeth, middle awn 3-6 inm. long, horizontal, coiled at the base in maturity. 

 Sterile sandy or gravelly soil, Me. to Mo. and southw. Aug. -Oct. FIG. 84. 



Var. Curtissii Gray. Differs in being less freely branched ; panicles looser ; 

 glumes unequal, the second 10-12 mm. long, the first f-f as 

 long; lemma 7-10 mm. long, excluding the awns. Va. to 

 Mo., and southw. 



2. A. basiramea Engelm. Resembling A. dichotoma, freely 

 branching at the base ; culms sparingly branched; leaves aver- 

 aging longer ; panicles looser, the terminal often partly included 

 in the upper sheaths, small panicles commonly borne in the 

 basal sheaths ; glumes acuminate, unequal, second 12-14 mm. 

 long, the first about as long ; lemma about 1 cm. long, exclud- 

 ing the awns ; lateral awns 2-7 mm. long, erect or spreading, 

 middle awn 1-2 cm. long. Dry soil and prairies, 111. to 

 Minn, and Neb. Aug., Sept. 



;]. A. ramosissima Engelm. Culms tufted, wiry, repeatedly branching, the 

 branches divergent; leaves mostly setaceous; panicle loose, few-flowered ; glumes 

 1.5-2.5 cm. long, awned from a bifid apex, unequal, the second equaling the 

 lemma (excluding the awns); lemma 2-2.3 cm. long; 

 N. lateral awns minute, erect, middle awn 2-3 cm. long, 



x. \i reflexed by a loose spiral at base. Dry prairies, Ind. 



^X^ | and 111. to Tenn. and Mo. Aug., Sept. 



^*""-^^ 1 4. A. gracilis Ell. Culms slender, in small tufts or 



^J solitary, branched at the base, simple or sparingly 

 I ft branched above, 1.5-5 % cm. high ; sheaths not loose; blades 

 l\| 2 mm. or less wide, usually involute in drying ; spikelets 

 If mostly in a slender raceme (if a panicle, the branches 

 M rarely bearing more than 2 spikelets), rather distant below, 

 if often crowded above ; glumes unequal, the second equal- 

 \ ing the floret ; lemma about 6 mm. long, usually mottled ; 

 middle awn horizontal, 8-15 mm. long, lateral awns erect, 

 2-6 mm. long. Sandy soil, N.H. to Mo., and southw. 

 Sept. FIG. 85. 

 A. intermedia Scribn. & Ball. Similar to the preceding but much larger 



85. A. gracilis. 

 Spikelet x 2. 



Sept. 



5- 



culms 3-7 dm. high, more freely branching, often geniculate at base; leaves 

 5-15 cm. long, rigid, involute ; panicle 2-4 dm. 

 long, slender, branches short, appressed ; 

 glumes attenuate-aristate, subequal or the 

 second longer, 7-9 mm. long, scabrous, slightly 

 shorter than the floret ; lemma scabrous above 

 the middle, sometimes mottled ; awns all 

 spreading, the middle one 18-22 mm. long, 

 lateral ones 14-17 mm. long, all variable. 

 Dry soil, la. and Kan. to Miss, and Tex. Aug. 



6. A. oligantha Michx. Culms tufted, wiry, branched 

 at base and at all the nodes, 3-6 dm. high ; sheaths loose 

 blades long, usually involute ; panicle or raceme few-flowered, 



the axis often flexuous and spikelets spreading ; glumes unequal, 

 long-awned from a bifid apex, exceeding the floret, the second strongly 

 7-nerved ; lemma 17-20 mm. long, scabrous above ; awns nearly equal, 

 divergent, 3.5-7 cm. long. Dry sterile soil, N. J. to Neb., and southw. 

 FIG. 80. 



7. A. tuberculbsa Nutt. Culms branched below, 1.5-5 dm. high, 

 tumid at the joints; leaves long and involute; panicles rigid, loose, 

 the branches in pairs, one short and about 2-flowered, the other 

 elongated and several-flowered ; glumes 2.5 cm. long, including 

 their slender-awned tips; lemma 12-15 mm. long, the twisted 



se of the awns of equal length ; awns divergent, subequal, 

 cm. long. Dry sandy soil near the coast, Mass, to Miss. : 

 Jreat Lakes. Aug.-Oct. (Mex.) FIG. 87. 



86. A. oligantha. 



Spikelet x %. 



and about the 



