50 BULLETIN 1074, U. S. DEPARTMENT OP AGRICULTURE. 



KEY TO THE SPECIES OR SUBSPECIES. 



la. Terminal spikelets fertile; palea remaining entire at maturity; 

 spikelets with 2 to 5 fertile florets. 

 2a. Glumes shorter than the lemmas, firm; palea as long as the 

 lemmas. ( Triticum sativum Lam.) 

 3a. Rachis tenacious; kernels separating from the chaff when 

 thrashed. 

 4a. Glumes distinctly keeled only in the upper half; lemmas 

 awnless or awns less than 10 cm. long; straw hollow. 

 5a. Spikes usually long, dense to lax, somewhat dorsally Page. 



compressed. ( T. aestivum L., T. vulgare Vill.) Common Wheat 50 



5b. Spikes short, dense, laterally compressed. ( T. 



compactum Host.) Club Wheat 172 



4b. Glumes sharply keeled at the base; lemmas usually 



awned; awns 10 to 20 cm. long; straw usually solid. 



5a. Glumes and kernels short; kernels ovate, with 



truncate tips. ( T.turgidum L.) Poulard Wheat 180 



5b. Glumes and kernels longer; kernels usually ellipti- 

 cal. ( T. durum Desf.) Durum Wheat 183 



3b. Rachis fragile; kernels inclosed in glumes when thrashed. 

 4a. Spikes dense, laterally compressed; pedicel short, 

 slender, usually attached to base of spikelet; shoulders 

 wanting to narrow, usually oblique. ( T. dicoccum 



Schrk.) Emmer 193 



4b. Spikes lax, narrow; pedicel long, wide, attached to face • 

 of spikelet below; shoulders wide, square. ( T. 



spelta L. ) Spelt 195 



2b. Glumes as long as or longer than the lemmas, papery, lanceolate; 

 palea of lower flowers half as long as their lemmas. ( T. 



polonicum L. ) Polish Wheat 197 



lb. Terminal spikelets sterile, often scarcely visible; palea falling into 

 two parts at maturity; spikelets usually with only one fertile 

 floret. 

 2a. ( T..monococcum L.) Einkorn 198 



COMMON WHEAT. 



In the Species Plant arum, Linne (IJfO) first used the-fiame aestivum 

 for a part of the common and club wheats. This name originally 

 referred to the awned spring forms. It has recently been used by 

 some authors for the name of the subspecies commonly recognized 

 as Triticum sativum vulgare. This name was applied to the com- 

 mon wheats by Villars in 1787, after it was pointed out that Linne's 

 separations were not logical or correct. The name vulgare is usually 

 preferred, because it means common, and has been almost universally 

 accepted for more than 100 years. 



Common wheat is distinguished from the other species or sub- 

 species by a spike long in proportion to its thickness. The spike 

 is usually dorsally compressed and is thus wide when seen in face 

 view of the spikelets instead of narrow, as with those of some other 

 divisions. The spikelets are 2 to 5 flowered, far apart, only slightly 

 overlapping, pressed close to the rachis, and nearly erect. The 

 glumes are keeled only in the upper half, shorter than the lemmas, 

 firm, and either glabrous or pubescent. The lemmas are awnless or 

 have awns less than 10 cm. long. The palea is as long as the lemmas 

 and remains entire at maturity. The culm of the plant usually is 



