184 
BtXLETIX 1074, U. S. DEPAETMEXT OF AGEICrXTTEE. 
in 1919 is shoTvn in Figure 75. The duriinis furnish the great bulk of 
the world's supply of wheat for the manufacture of semolina, maca- 
roni, and spaghetti. The production of durum wheat in the "United 
Fig. To. — Ouiline map of the Fuited Srates, showing the distribution of durum wheat in 
1919. Estimated area, 4,340^000 acres. 
States made possible a large macaroni industry, which now uses 
about a third of the national production of this wheat. The re- 
mainder is exported or used by American mills or bakerie- for mix- 
ing with other wheats or flour for bread making. 
The varieties that are commercially grown are distinguished by the 
accompanying key. 
KEY TO THE VARIETIES OF DURUM WHEAT, 
la. Spike AvryrED. 
2a. GL13CES Glabeous. 
3a. Glumes White. 
4a. Awxs White. 
5a. E:ER^'ELS Red {Triucum durum afnne Kcke.). 
Kerntls Midlong, Haed Textad 
4b. Avrxs Black. 
5a. Kernels White (Amber) {T.d. Uucomtlan Al.). 
Keexels Very Long, Hard Peliss 
3b. Gleties Yellow. 
4a. Awxs White. 
5a. Keen-els White ( T. d. hordei/ormf Host.). 
Kern-els Loxg, Hard. 
Spike fusiform. 
Plant midtall: beaks 1-2 mm. long Acme 186 
Monad 187 
Page. 
1S5 
1S6 
Plant tall: beak^ 1-5 mm. long Akkatttk-^. 
MlN-DXTil 
Spike oblons: plant tall. 
Beaks 1-2 mm. long Ktjbaxka 
KCBAKKX Xo. *^. 
BrroED 
Beaks 1-10 mm. long Maboeant 
187 
isd 
190 
190 
190 
