603 
Cultivated Plants of the Fiihire. 
cvzroM 
traditions to t^e other cereals, and the varieties are correspondingly 
numerous. It is said that in Japan above three hundred varieties 
are grown on irrigated lands, and more than one hundred on up- 
lands. 
With the possible exception of rice, not one of the species of 
cereals is certainly known in the wild state. 
It is out of our power to predict how much time would elapse 
before satisfactory substitutes for our cereals could be found. In 
the improvement of the grains of grasses, other than those which 
have been very long under cultivation, experiments have been few, 
scattered, and indecisive. Therefore, we are as badly off for time- 
ratios as are the geologists and archeologists in their statements of 
elapsed periods. It is impossible for us to ignore the fact that tliere 
appear to be occasions in the life of a species when it seems to be 
peculiarly susceptible to the influences of surroundings. A species, 
like a carefully laden ship, represents a balancing of forces within 
and without. Disturbance may come through valuation from 
within, as from a shifting of the cargo, or in some cases from with- 
out. We may suppose both forces to be active in producing varia- 
tion, a change in the internal condition rendering the plant more 
susceptible to any change in its surroundings. Under the influence 
of any marked disturbance, a state of unstable equilibrium may be 
brought about, at which times the species as such is easily acted 
upon by very slight agencies. 
One of the most marked of these derangements is a consequent 
of cross-breeding within the extreme limits of varieties. The 
resultant forms in such cases can persist only by close breeding, or 
by propagation from buds, or the equivalents of buds. Disturbances 
like these arise unexpectedly in the ordinary course of nature, 
giving us sports of various kinds. These critical periods, however, 
are not unwelcome, since skilful cultivators can take advantage of 
them. In this very field much has been accomplished. An attentive 
study of the sagacious work done by Thomas Andrew Knight shows 
to what extent this can be done.' But we must confess that it 
would be absolutely impossible to predict with certainty how long 
or how short would be the time before new cereals, or acceptable 
equivalents for them, would be provided. Upheld by the confidence 
which I have in the intelligence, ingenuity, and energy of our ex- 
periment stations, I may say that the time would not probably 
exceed that of two generations of our race, or half a century. 
In now laying aside our hypothetical illustration, I venture to 
ask why it is that our experiment stations, and other institutions 
dealing with plants and their improvement, do not undertake in- 
vestigations like those which I have sketched ? Why are not some 
of the grasses other than our present cereals studied with reference 
to their adoption as food grains 1 One of these species will naturally 
' A Selection from the Physiolojical and Horticultural Papers, published 
in the Transactions of the Eoyal and Horticultural Societies, by the late Thomas 
Andrew Knight, Esq. London, 1841. 
