168 
Origin of Wheat. 
the number of the ribs of the glume is G or 7 ; when the glume 
has 3 awns, the number of ribs is commonly 10, 5 strong alter- 
nating with 5 slender. The asperities which have already been 
stated to cover the sides of the glume and the awns render both 
rough to the toucli. 
The seed or grains of this species are 1 ccntim. in length, 
horny, slender, not being more than 3 millim. in circumference 
at their largest part. Their upper end is terminated by a tuft 
of whitish silky hair. Tliese grains are of a fine yellow colour, 
and become brown when dried ; they are a little floury when 
broken. When germinating, only 2 radicles are usually pro- 
duced ; 3 are rare. 
The plant is glaucous all over. Of all the species we shall 
have to notice this is capable of being the most highly developed. 
It never produces varieties. 
2. ^(jilops ovata, L. The glume of this species is composed 
of 2 equal valves, each of which is terminated by 4 awns. The 
valves are marked with 10 or 11 projecting nerves, of which 6 
or 7 are strong, and the others alternating are weak and often 
incomplete ; all are glabrous, or are furnished with very short 
hairs ; the spikelets which they cover are strongly convex. 
Of the 2 membranous valves or palece which compose the 
floret, one is terminated by 3 sliort awns, and the other has no 
beard, but is slightly ciliated at its apex. 
The flowering stems are from 20 to 25 centim. in height. 
The upper leaves never reach the first tooth of the axis of the 
ear. The ear, including the awn, is 4 centim. long ; the 
end of the awn is violet-coloured. These awns spread so as to 
form nearly a right angle with the axis of the ear. The spikelets 
are 4 in number, and the 2 lower ones alone are fertile. 
The ears of this species are shorter than those of any other. 
The fruit or grains are much shorter than those oi triwicialis. 
Some are yellow and floury when broken, the others are black and 
horny. Three radicles are produced when the seeds germinate. 
The whole plant is glaucous in appearance, and is thus easily 
distinguished at a glance from the other species. 
3. JEgilops triaristata, Willd., difi'ers from the 2 species just 
described in the following particulars : the 2 valves of the glume 
are equal as before, but they are almost always terminated by 3 
awns, very rarely by 2. The ridges and nerves of the valves are 
less numerous than in jE. ovata. The valves of the floret, or 
■palecc, are membranous, as in the other two species ; but one 
is ciliated at its edges, and is terminated by 2 short awns, whilst 
the other has no awn, and is ciliated at its apex. The awns are 
nearly vertical. 
The flowering stems of this species are much more erect and 
