Page:Popular Science Monthly Volume 82.djvu/38

34 separating species from varieties, that is, their sterility when crossed among themselves, or their failure to produce fertile offspring. Attempts to cross these types have never given results.

Ordinary wheat may be divided into numerous varieties or subspecies, reciprocally fertile, which are grouped about the following subspecies:

 Emmer (T. dicoccum). Spelt (T. spelta). Wheat proper (T. tenax).

The first two subspecies differ from the third in that the ear has a fragile rachis and the grains remain covered by glumes which must be removed by a somewhat complicated process, whereas in the third species the grains on ripening fall from the ear the rachis of which is not articulated. I shall give here only what is most essential for the understanding of what is to follow. Now, it is evident that emmer and spelt are inferior to true wheat because of the fragility of the rachis of the ear and because of their enclosed grains. Whenever it is possible wheat is grown instead of emmer or spelt.

Not to prolong the discussion of these classifications, let us say at once that wheat proper is represented in cultivation in various parts of the world by a considerable number of varieties, but it is difficult even for the specialist to distinguish them. One of these varieties, having a non-articulated rachis (Triticum durum), the hard wheat of the Mediterranean countries, is so closely related to emmer that the systematic affinity of the wheats with an articulated rachis and those with a non-articulated rachis can not be questioned. Each year, in agricultural experiment stations organized according to the principles of Vilmorin, Eimpau or Svalöf, new races are brought to light and are tested out in suitable soils and climates. I do not wish to tire you by a dry enumeration of all these forms; even had I the time for it I should not be competent to perform this task.

Which of all these varieties of cereals first appeared in cultivation? To this question we may reply that it is certain to-day that emmer was cultivated by the Egyptians from the time of the first dynasty, or about 6,000 years ago. The glumes preserved in the tombs show that the grain was already at that time freed from its envelopes by the use of special machines; it was not simply flailed or tramped out by cattle. Einkorn and emmer have also been found among the debris of the granaries of the lake-dwellers of Switzerland. Hard wheat, which of all the kinds of wheat proper most nearly resembles emmer, has also been cultivated in Egypt since very ancient times. If we regard the