FLORA OF THE DISTRICT OF COLUMBIA. 91 



52. SECALE L. 

 1. Secale cereale L. Rye. 



Occaaional along roads and in the vicinity of grain fields. Jime. Cultivated for 

 grain and forage; native of the Old World. 



53. TRITICUM L. 

 1. Triticum aestivum L. Wheat. 



Vicinity of elevators and waste land where the seed has been accidentally scattered. 

 June. Xot established in our flora. Native of the Old World. (T. vulgare Vill.) 



54. HORDEUM L. Barley grass. 

 Plants perennial. 



Awns 4-5 cm. long 1. H. jubatum. 



Awns usually not over 1 cm. long 2. H. nodosum. 



Plants annual. 



Glumes, at least some of them, ciliate 3. H. murinum. 



Glumes not ciliate. 



Awns as much as 10 cm. long; blades 5-10 mm. wide 4. H. vulgare. 



Awns 1-1.5 cm. long; blades narrow 5. H. pusillum. 



1. Hordeum jubatum L. Squirreltail grass. 

 Open ground; rare. July. Western U. S.; introduced in the eastern U. S. 



2. Hordeum nodosum L. 



Open dry ground; infrequent. June. Common in the western U. S.; also in 

 Eur. and Asia. 



3. Hordeum murinum L. 



Waste places; rare. Introduced from Eur. 



4. Hordeum vulgare L. Barley. 

 Along railroads and in waste places; occasional. June. Cultivated as a cereal; 



native of the Old World. 



5. Hordeum pusillum Nutt. 



Open dry ground; rare; Canal Road (Steele). June. Western U. S.; sparingly 

 introduced in the eastern U. S. 



55. ELYMUS L. Wild rye. 



Glumes subulate, not indurate at base, with about 2 strong nerves; culms slender. 



Lemmas pubescent I.E. striatus. 



Lemmas glabrous la. E. striatus arkansanus. 



Glumes narrow but not subulate, indurate at base, about 5-nerved. 



Spike nodding; awns curved-spreading; glumes divergent but not much bowed-out 



at base 2. E. canadensis* 



Spike erect; awns straight; glumes bowed-out at base, the induration prominent. 



Glumes and lemmas glabrous 3. E. virginicus. 



Glumes and lemmas hirsute. 



Awn not longer than the lemma 3a. E. virginicus hirsutiglumis. 



Awn long and somewhat spreading 4. E. australis. 



1. Elymus striatus Willd. 



Rocky woods; frequent. Summer. Northern states, south to Va. 

 la. Elymus striatus arkansanus (Scribn. & Ball) Hitchc. 



Rocky woods; rare; along the Potomac above the fall line. Summer. Southern 

 states, north to Md. 



2. Elymus canadensis L. Wild rye. 

 Open low ground; rare; Fourmile Run (Dewey). July. Eastern LI. S. 



