106 



BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



appearing like halves of a single split glume ; lemma lying next to the 

 axis, smaller than the glumes, hyaline, keeled, scarcely more than 

 1-nerved ; palea a little shorter than the lemma, hyaline, 2-nerved. 



Low annuals, with cylindric spikes. Species four, in the Eastern 

 Hemisphere, one introduced into the United States. 



Type species : Roffboellia pannonica Host. 



Pholiurus Trin., Fund. Agrost. 131. 1820. Based on a single species. Rott- 

 boellia pannonica Host. This species has 2-flowered spikelets. 



Lepiurus Dumort., Obs. Gram. Beige 140, pi. 15, f. 57. 1823. A single species 

 based on " Rottbolia incurvata L." fils. 



The species of Pholiurus have been referred by most recent authors 

 to Lepturus, the type of which was, by 

 the same authors; referred to Monerma. 



Our species, Pholiurus incurvatus (L) . 

 Hitchc. (Aegilops incurvata L., 1 Lep- 

 turus filiformis (Eoth.) Trin.) (fig. 54), 

 has 1-flowered spikelets. It is intro- 

 duced along the borders of salt marshes 



FIG. 54. Pholiurus incur vatuti. Plant, x i ; spikelet with a joint of the rachis, X 5 ; 



spikelet, front view, X 5. 



from Maryland to Virginia and from Marin County to San Diego, 

 Calif. It has no economic value. 



4. AVENEAE, THE OAT TRIBE. 



44. KOELERIA Pers. 



Spikelets 2 to 4 flowered, compressed, the rachilla disarticulating 

 above the glumes and between the florets, prolonged beyond the per- 

 fect florets as a slender bristle or bearing a reduced or sterile floret at 

 the tip ; glumes usually about equal in length but unequal in shape, 

 the lower narrow and sometimes shorter, 1-nerved, the upper some- 

 what broader above the middle, wider than the lower, 3 to 5 nerved ; 



1 Sp. PI. ed. 2. 2: 1490. 1763. 



