GRAMINEAE (GRASS FAMILY) 



141 



* Spikelets more than 2 cm. long ; annuals. 



1. A. rAxuA L. Culms 4-12 dm. high, in small tufts, erect, stout ; blades 

 long, 5-8 mm. wide; panicle loose and open, the slender branches ascending; 

 spikelets pendulous, 2.2-2.5 cm. long, excluding the awns ; 



glumes smooth, striate, acuminate ; florets approximate ; 

 lemmas with a ring of hairs at base and more or less 

 appressed-pubescent with long stiff brownish hairs; awn 

 inserted about the middle, bent and twisted, 3 cm. long 

 or more. Fields and waste places, Ont. and O. (rare) ; 

 Wise., 111., and westw. (Nat. from Eu.) FIG. 124. 



2. A. STERILIS L. (ANIMATED OATS.) Larger than 

 the preceding, the spikelets 3.5-4.5 cm. long, excluding 

 the awns ; lemmas usually more densely hairy ; awns 

 5-7 cm. long. Occurs sparingly in N. J. and near Phila- 

 delphia, Pa. (Adv. from Eu.) 



A. SATIVA L., the cultivated oat, commonly occurs in 

 waste places in cities, etc. (Introd. from Eurasia.) 



* * Spikelets less than 1.5 cm. long ; perennials. 



3. A. PDBESCENS Huds. Culms 6-9 cm. high, in small tufts, erect, slender ; 

 sheaths and blades, at least the lower, retrorsely pubescent ; panicle rather nar- 

 row, the slender flexuous branches erect; spikelets upright, 1.2-1.3 cm. long, 

 excluding the awns ; glumes 3-nervsd, the nerves scabrous ; florets approximate, 

 rhachilla-joints clothed with long white hairs ; lemmas scabrous, a tuft of white 

 hairs at the base, a bent and twisted awn inserted about the middle, 2-2.5 mm. 

 long. Fields, Vt., N. J. (Adv. from Eu.) 



124. A. fatua. 

 Spikelet x %. 



46. ARRHENATHERUM Beauv. OAT GRASS 



Spikelets 2-flowered, the florets approximate, the lower staminate, its lemma 

 bearing a geniculate and twisted awn on the back near the base ; the upper per- 

 fect, its lemma short-awned from or near the apex, or awnless ; rhachilla hairy, 

 prolonged behind the upper palea into a bristle ; glumes unequal, acute, thin 

 and scarious ; lemmas of firmer texture, 5-7-nerved ; palea 

 ciliate on the nerves. Tall perennials with flat leaves and 

 long narrow panicles. (Name from &pptjv, masculine, and 

 dd-rjp, awn, in reference to the awned staminate floret.) 



1. A. ELATIUS (L.) Beauv. (TALL O.) Culms 1 m. or more 

 high, erect; leaves long, linear, 0.5-1 cm. wide, scabrous on 

 both surfaces ; panicle pale or purplish and shining, 15-30 cm. 

 long, narrow, the short branches verticillate, usually spike- 

 let-bearing from the base ; spikelets 7-8 mm. long ; glumes 

 P d'etaled x 2 UmeS mutely scabrous, the second about equaling the florets ; 

 lemmas scabrous, the awn of the staminate floret about twice 

 the length of its lemma ; paleas as long as their lemmas. (A. avenaceum 

 Beauv.) Meadows and waste places,. Nfd. to Va., Ont., Minn., etc.; often 

 cultivated. June, July. (Nat. from Eu.) FIG. 126. 



1'25. A. elatius. 



47. DANTHdNIA DC. WILD OAT GRASS 



Spikelets several-flowered ; florets not closely approximate, uppermost imper- 

 fect or rudimentary ; glumes subequal, much longer than the lemmas, usually 

 exceeding the uppermost floret ; lemma convex, 2-toothed or bifid at the apex, 

 with a twisted awn between the teeth ; awn flat, formed by the extension of the 

 3 middle nerves of the lemma. Tufted erect perennials with narrow leaves and 

 small terminal panicles or racemes. (Named for iZtienne Danthoine, a botanist 

 of Marseilles.) 



