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THE PRINCIPLES OF BOTANY. 
“ The Hordeum distichum is the only kind of barley that 
has been found apparently wild. We have now before us 
specimens gathered in Mesopotamia during Col. Chesney's 
expedition to the Euphrates, with narrow ears, a little more 
than an inch long, exclusive of the awn, or four and a half 
inches, awns included; and others from the ruins of Per- 
sepolis, with ears scarcely so large as starved rye. Both are 
straw-colour, but that from Mesopotamia has the glumes 
much more hairy than the other.” The plant is also said to 
inhabit Tartary. The report that it grows wild in Sicily 
seems to have arisen from the Mediterranean HEgilops ovata 
having been mistaken for it. To this species belong all the 
varieties of Cereal Barley. When, then, we consider that 
some kinds of barley have two rows of seeds to each ear, 
others four, and others again six, it becomes a curious sub- 
ject for inquiry how such different forms can have proceeded 
from one species. The morphology of this matter can 
hardly be better explained than by quoting the following 
description of the Hordeum pratense , a common pasture 
species : 
“ Spike one and a half to two inches long, close and cylin- 
drical. To each notch are three pairs of awn -like, rough 
glumes ; within the central pair is a flowering glume, lanceo- 
late. but completely rolled round the flower, and tapering into 
an awn as long as itself ; within each of the two lateral pairs 
is usually an inner glume, smaller than the central one, 
either empty or enclosing a male or rudimentary flower.” — 
f Bentham's Handbook of the British Flora/ 
The nature of these changes may be best understood by 
the following digrammatic arrangement : 
H. DISTICHUM. H. SlBERICA. H. HEXASTICHUM. 
0 0 
oOo gOg ° 0 ° 
° ° 0 0 
Two -rowed by 
abortion of four rows. 
Four-rowed by 
abortion of two rows. 
The seeds of a spikelet. 
Six-rowed by 
the fruition of all 
the rows. 
1. H. distichum. — The varieties of two-rowed barley are 
those mostly cultivated, and indeed it is to them that the 
term barley is usually applied, the four- and six-rowed sorts 
getting the name of big or here. Of the two-rowed barley 
are several varieties in cultivation, among the best of which 
are the Chavelier and the common English barley. The 
