50 BULLETIN 1074, U. S. DEPAETMEXT OF AGKICULTUEE. 
KEY TO THE SPECIES OR SUBSPECIES. 
la. Terminal spikelets fertile; palea remaining entire at maturity; 
spikelets witti 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 chafE when 
thrashed. 
4a. Glumes distinctly keeled onlyin 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; lenunas 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.) DuEUM 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.) Emmee 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.) Eixkokn 198 
COMMON WHEAT. 
In the Species Plantariun, Linne (UO) 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 sativuin 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 
