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Genus 37. AVENA. Oat Grass. 



Gen. Chak. Inflorescence paniculate, loose and spreading. Spike- 

 lets stalked, laterally compressed, two- or more-flowered, the 

 upper flowers (when more than two are present) often barren or 

 rudimentary. Glumes two, membranaceous, equal to or exceed- 

 ing the flowers in length. Palese two, lanceolate, often hairy at 

 the base, eventually hardening and inclosing the fruit ; the lower 

 one two-pointed at the apex, with a long, kneed, and twisted 

 dorsal awn. 



The genus may include between thirty and forty species, several of 

 them, however, being doubtfully distinct. Their distribution, chiefly 

 in the northern hemisphere, is almost exclusively confined to its tem- 

 perate and colder regions, those which are found within the tropics 

 occurring only at considerable elevation. With the exception of the 

 cultivated oats, the annual species are usually considered as useless 

 weeds ; the perennial ones are generally liked by cattle, and some are 

 valuable pasture grasses. 



The name is Latin, but its derivation cannot be traced. 



The genus Trisetum, separated from this by Persoon, is not adopted 

 here, as botanists difiFer in regard to their allotment of the species, but 

 the following sections are worthy of attention by the student. 



* Outer glume five- to seven-veined, inner one five- to eleven-veined. 

 Outer palea six- to eight-veined. Spikelets ultimately drooping. 

 Plants annual. 



AvBNA PATUA. Wild Oat. Hover. Plate CIX. 



Panicle erect. Spikelets drooping, usually three-flowered. Flowers 

 scabrous, hairy at the base, shorter than the glumes. Outer palea 

 bifid at the apex. Awn very long. 



Avena fatua, imnoews. ^. jB. 2221 ; ed. 2. 161. Generally adopted. 



A frequent weed in corn-fields, especially among barley, and found 

 occasionally by road-sides and on waste ground, but certainly not 

 indigenous. Stems two or three feet high, smooth. Leaves Unear, 

 pointed, rough to the touch. Ligule obtuse. Inflorescence usually a 

 simple panicle, the peduncles being very rarely branched, widely 

 spreading and sometimes more than a foot in length. Spikelets droop- 

 ing, pendulous when in fruit, usually three-flowered. Glumes nearly 

 equal, smooth, acute, membranaceous ; the outer smaller, seven-veined, 

 the inner eleven-veined ; both carinate and strongly ribbed. Flowers 

 much shorter than the glumes. Outer palea bifid at the point, eight- 

 veined, with long fulvous hairs at the base ; inner palea shorter, with 

 two green, marginal, minutely ciliated veins. Awn very long, (more 

 than twice the length of the flower), knee-bent and twisted. 



