6 BULLETIN 1074, U. S. DEPARTMENT OF AGRICULTURE. 
Harz, in 1885 (704), classified and described a large number of 
wheats in a manner similar to that of Koernicke and Werner. The 
common and club wheats were considered as a single species. 
Hackel, in 1887 (201), classified the genus Triticum according to 
a key very similar to the one adopted by Koernicke and Werner. 
Hackel recognized three species, satzvwm Lam., monococcum L., and 
polonicum L.; and three races of sativum, namely, spelta, dicoceum, 
and tenax. In the latter he included vulgare, compactum, turgidum, 
and durum. as subraces. 
Vilmorin, in 1889 (199), grouped the wheats into 50 sections, 
according to their leading characters. Each section was briefly de- 
scribed and the synonyms were given. The common and club wheats 
were considered as one species. 
Eriksson, in 1895 (88), subdivided the botanical groups of 
Koernicke and Werner into smaller groups which he called subvarie- 
ties, based chiefly on the density of the spike, the thickness of the 
kernel, and the length of the rachis. He also gives an excellent re- 
view of the literature on wheat classification. 
Heuzé, in 1896 (7/2), published a second edition of his “Les 
Plantes Céréales,” in which were included rather complete histories 
and descriptions of the varieties of wheat. : 
Cobb, in 1896 (69), keyed 54 varieties of wheat which he was 
growing in New South Wales, Australia, using the leading plant, 
spike, and kernel characters. In 1905 (72) he proposed to classify 
wheat varieties by a microscopic examination of the aleurone layer. 
This method, however, is impracticable for classification purposes in 
the field, or even with certainty in the laboratory, when closely re- 
lated varieties are considered. 3 . 
Howard and Howard, in 1909 (721), classified the wheats of India 
largely according to the methods of Koernicke and Werner and of 
Eriksson. They (720) also consider in detail the characters used in 
classification. 
Richardson, in 1913 (758), described many of the wheats of Aus- 
tralia and gave the history of each variety. He did not arrange them 
in a classified order. | 
The Union of South Africa in 1919 (781) published descriptions 
and synonyms of the wheat varieties of South Africa which also 
designated the areas where the varieties should be grown in that 
country. 
Ducellier, in 1920 (82), published a classification and descriptions 
of the wheats of the Hoggar and oasis regions of Algeria. Only a 
few varieties were fully described. 
