288 OHIO BIOLOGICAL SURVEY 



purplish panicle, the short branches verticillate and usually spikelet- 

 bearing from the base. Lemma scabrous, the awn of the staminate 

 flower about twice the length of its body. 



A grass cultivated to some extent for hay. In fields and waste 

 places. June, July. From Europe. Hamilton County. 



17. Trisetum Pers. False-oats. 



Tufted perennial grasses with spike-like or open panicles. 

 Spikelets 2-5-flowered, rachilla prolonged beyond the flowers ; empty 

 glumes unequal, keeled; lemma 2-toothed, keeled, bearing a dorsal 

 awn ; palet narrow, 2-toothed ; grain free, enclosed in the flowering 

 glumes. 



1. Trisetum pennsylvanicum (L.) Beauv. Marsh False-oats. 

 A grass with an erect, slender, often weak stem, 1-3 ft. high, and 

 with a narrow or sometimes loose and nodding yellowish panicle, 

 the branches ascending. Spikelets 2-flowered ; lemma of the lower 

 flower with a small awn ; lemma of the upper flower with a long, 

 bent and twisted awn. 



In swamps and wet meadows. June, July. No specimens. 



18. Avena L. Oats. 



Annual or perennial grasses with terminal panicles of large 

 spikelets. Spikelets 2-many-flowered, rachilla bearded below the 

 flowers ; empty glumes subequal, membranous, many-nerved ; lem- 

 mas indurated toward the base, generally bearing a dorsal awn ; 

 palet narrow, 2-toothed ; grain often adherent to the flowering 

 glumes. 



1. Empty glumes much shorter than the spikelets ; flowers with a circle of short 

 bristles around the base; perennials: A. torreyi. 



1. Empty glumes as long or longer than the spikelets exclusive of the awns; 

 annuals. 2 



2. Lemmas pubescent with long bristles; awns long and stiff. A. fatua. 

 2. Lemmas glabrous ; awn comparatively short and weak, or absent. A. sativa. 



1. Avena torreyi Nash. Purple Oats. A perennial grass with 

 an erect simple slender stem, 1-2 ft. high, and a lax panicle, the 

 branches erect or ascending, naked below. Spikelets 3-6-flowered ; 

 lemma scabrous, strongly nerved, with a ring of short hairs at the 

 base, and with an awn as long as its body or longer. 



In woods. July, August. Franklin County. 



2. Avena sativa L. Common Oats. An annual glabrous grass 

 with a hollow stem, 1-4 ft. high, and a loose ample panicle with as- 

 cending branches. Spikelets about 1 inch long; lemma glabrous, 

 awnless or with a small straight awn slightly twisted at the base. 



