EXPERIMENTS WITH DURUM WHEAT. 9 
of other wheats. Production was reduced again during the years 
1913 and 1914. This smaller production was responsible in part for 
the higher price which was obtained for the crop during these years. 
In 1915 production increased sharply in response to the stimulus of 
good prices and increasing demand. Since the fall of 1911, as noted 
previously, the price of durum wheat usually has been equal to or 
slightly better than that obtained for common spring wheats. (See 
fig. 1.) Several causes have contributed to this. Among them are 
(1) better f acuities for mining these hard wheats, (2) increasing use 
for making macaroni in this country, and (3) increasing export de- 
mand. Figure 3 is a map showing the production of durum wheat 
in Minnesota, South Dakota, North Dakota, and Montana in 1915, 
according to the figures of the Bureau of Crop Estimates. 
DESCRIPTION AND KEY. 
In the genus Triticum, durum wheat has been regarded as one of the 
seven or eight species or subspecies. The writers are not concerned 
with its taxonomic status at this time, but merely with those char- 
acters which mark the durum wheats as distinct from the common 
wheats. 
DESCRIPTION. 
Durum wheat differs from common wheat in the characters of both 
plant and kernel. The'durum plant usually is taller (fig. 4) and more 
vigorous than that of common wheat varieties; the culms are thicker 
and the leaves broader. The spikes average broader and shorter (see 
Qg. 9) than those of common wheat and are much more compact. In 
some varieties they are so short and broad as to be veritable club 
wheats. 
The crowding of the spikelets on the rachis, together with the large 
size of the kernel, results in a characteristic outcurving or expansion 
of the spikelet which widens the spike on both sides of the rachis. As 
a result, the spike is flattened transversely to the plane of the rachis 
or to the plane of the face of the spikelets (&g. 5) instead of parallel 
with it, as in the case of common wheat. 
The awns of durum wheat are much longer than those of any variety 
of common wheat. They vary in length from 1 to 2 J decimeters or 
more. The long, stiff awns and the compact head give the plant 
much the appearance of barley, for which it is often mistaken by 
those not familiar with the crop. 
The kernels of durum wheat are larger than those of common wheat 
(fig. 6), varying from about 7 to 10 mm. in length, with an average 
length of 8 to 8 i mm. As the name indicates, the kernels are very 
hard, the endosperm being entirely corneous. The seed coats are 
unpigmented. The effect of the completely corneous endosperm and 
unpigmented seed coats is a kernel of a clear amber appearance, 
14644°— 18— Bull. 618 2 
