328 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8. 
port what we do not produce. This puts us at the mercy of other nations 
in ways of which we have had recent illuminating examples. Third, an 
undertaking to increase our own production of food to keep pace with in- 
crease of population. This last is the only satisfactory decision. How 
may this result be accomplished? 
There are two chief lines of attack on the problem of increasing our 
food supply. One is to increase the area under cultivation, by reclaiming 
desert areas through the more extensive and more productive use of irriga- 
tion waters, by the reclamation of swamp lands, and by the utilization 
of the untilled lands in the present tilled area. Some of these are problems 
in engineering, some in economics, some in soil science, and some in crop 
physiology. The other possibility is to increase the productivity of the 
areas already farmed. This requires progress in farm organization, soil 
science, animal husbandry, crop rotations, plant improvement, plant 
introduction, and the control of crop pests. Both methods present plant 
problems which challenge botany to her utmost endeavor. 
Botanic Families of Important Crop Plants 
We have seen that the crop plants vital to human welfare are those 
which furnish food, fodder, and medicine for man and his domesticated 
animals, clothing for him, and shelter for him and for them, and also for 
his industries. Plants from almost the entire range of the vegetable king- 
dom are requisitioned to provide material for one or another of these pur- 
poses. This realization recalls the promise of Scripture: 
And God said, " Behold, I have given you every herb yielding seed, which is upon 
the face of all the earth, and every tree which is the fruit of a tree yielding seed, to you it 
shall be for food " (Genesis i: 29, Am. Rev.). 
The three important classes of food plants for man are the cereals, the 
vegetables, and the fruits. 
Cereals 
No other botanic family is of such overwhelming significance to the 
human race as the grass family, Poaceae or Gramineae, which contains the 
cereals, corn, wheat, rye, oat, barley, rice, sorghum, and millet, as well as 
the most important hay, grazing, and silage crops. For those who like 
statistics, it may be of interest to note that the estimated value of the 
cereals grown in the United States in 191 7 was over $6,800,000,000; in 
1918 about the same; and in 1919, nearly $7,300,000,000. Out of sympathy 
for any botanists so unlucky as to own grain farms, the figures for 1920 
are omitted. 
A few other plants ordinarily are classed as cereals, though not truly 
such. Among these is buckwheat, belonging to so distant and unpromising 
a botanic family as the Polygonaceae, while the closely related family, 
Chenopodiaceae, contains quinua, a human food extensively used by the 
