298 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Figure 590. — Distribution of 

 Avena hookeri. 



58. ARRHENATHERUM Beauv. 



Spikelets 2-flowered, the lower floret staminate, the upper perfect, 

 the rachilla disarticulating above the glumes and produced beyond 



the florets; glumes 

 rather broad and 

 papery, the first 1- 

 nerved, the second 

 a little longer than 

 the first and about 

 as long as the spike- 

 let, 3-nerved; lem- 

 mas 5-nerved, hairy 



on the callus, the lower bearing near the 

 base a twisted, geniculate, exserted awn, 

 the upper bearing a short straight slender 

 awn just below the tip. Rather tall per- 

 ennials, .with flat blades and narrow 

 panicles. 'Type species, Arrhenatherum 

 avenaceum Beauv. 

 (A. elatius). Name 

 from Greek arren, 

 masculine, and 

 ather, awn, refer- 

 ring to the awned 

 staminate floret. 



1. Arrhenathe- 

 rum elatius (L.) 

 Mert. and Koch. 

 Tall oatgrass. 

 (Fig. 592, A.) 

 Culms erect, 1 to 

 1.5 m tall; blades 

 flat, scabrous, 5 to 

 10mm wide; pani- 

 cle pale or purplish, 

 shining, 15 to 30 

 cm long, the short 

 branches verticil- 

 late, spreading in 

 anthesis, usually 

 spikelet-bearing from the base; spikelets 7 to 8 mm long; glumes mi- 

 nutely scabrous; lemmas scabrous, the awn of the staminate floret 

 about twice as long as its lemma. % —Meadows, open ground, and 

 waste places, Newfoundland to British Columbia, south to Georgia, 

 Tennessee, Iowa, Idaho, and California; frequent m the Northern and 

 Eastern States; introduced from Europe and escaped from cultivation. 

 Cultivated in the northern humid regions as a meadow grass. 



Arrhenatherum elatius var. bulbosum (Willd.) Spenner. _ lu- 

 ber oatgrass. (Fig. 592, B.) Base of culm consisting of a series of 

 closely approximate corms (shrot subglobose internodes) 5 to 10 mm 

 in diameter. 91 —Occasionally introduced, Michigan, Virginia to 

 Alabama. Europe. 



Figure 589.— Avena 

 X.l; floret, X 5 



_ hookeri. Panicle, 

 (Seribner 372, Mont.) 



Figure 591. — Avena morto- 

 niana. Panicle, X 1; floret, 

 X 5. (Type.) 



