242 A T#HXT-BOOK OF GRASSES 
ting into 2 parts, the spikelets much compressed, 2-flowered but 
usually 1-seeded. 
266. Classification of the wheats—The cultivated 
forms of the genus Triticum may be divided into 2 series: 
(1) The spelt wheats, in which the axis disarticulates and 
the grains are permanently inclosed in the spikelets. This 
group includes spelt (7. spelta L.), emmer (7. dicoccum 
Schrank) and einkorn (T. monococcum L.), the latter, 
grown to a limited extent in certain parts of Europe, being 
distinguished by the 1l-awned spikelets with usually only 
1 grain. (2) The naked wheats, in which the axis is 
entire and the grains not permanently inclosed by the 
spikelets. In these the grain can be separated from the 
chaff by threshing. The group includes Polish wheat 
(T. polonicum L.), durum wheat (7. durum Desf.), Eng- 
lish wheat (7. turgidum L.) and the numerous varieties of 
wheat grown in America, 7. estivum L., T. vulgare Vill., 
and T. sativwm Lam. (See Jessen, Deutschlands Grdser 
191. 1863.) 
Hackel’s classification—Hackel divides the cultivated 
wheats into 3 species on more technical botanical char- 
acters: 
A. Terminal spikelet aborted, often scarcely 
visible. Palea falling into 2 parts at separ 
Lateral teeth of glumes acute.............. . T’. monococ- 
AA. Terminal spikelets developed; palea eee [cum. 
entire; lateral teeth of the glumes obtuse. 
s. Glumes shorter than any of the lemmas, 
chartaceous; palea as long as lemmas.. '2. T. sativum. 
BB. Glumes as long as or longer than any of the 
lemmas, papery, lanceolate; palea of the 
lowest flower half as long as its lemma....3. 7’. Pe 
Triticum sativum (the equivalent of JT. @stivum) he 
divides as follows into 3 groups which he calls races: 
