ORIGIN AND RELATIONSHIPS OF RACES OF WHEAT 343 



prostrate and erect habit of its young shoots, flinty and mealy grains, 

 immunity and susceptibility to attacks of fungi and other features, there 

 exists an almost continuous series of transition forms between their 

 extreme limits. 



Any interpretation of the origin of the vulgare race and with it the 

 rest of the Bread Wheat series must account for the racial characters 

 mentioned below, which differentiate T. vulgare from the Emmer series. 



(i.) The presence of a single line of long hairs on the summit of the 

 longitudinal ridges of the young leaf-blades, with shorter 

 ones or none at all on the sides of the ridges. 



(ii.) Thin- walled, hollow culms. 



(iii.) The exceptionally tough, non-disarticulating rachis. 



(iv.) The rounded back and absence of keel on the lower part of the 

 empty glume of a large proportion of the race. 



(v.) The comparatively short awns of the fully bearded ears, and the 

 occurrence of beardless and semi-bearded ears. 



The presumed prototypes of the Emmers possess none of these ; 

 they are, however, all found in Aegihps ovata, L., or A. cylindrica, Host, 

 and I have no doubt that both these species have entered into the con- 

 stitution of the vulgare race of wheats. 



The species named are wild annual grasses, the former widely dis- 

 tributed in the Mediterranean region from Portugal to Egypt, Syria and 

 Transcaucasia, the latter appearing in Italy, the Balkans, South Russia, 

 and Asia Minor. As already indicated, the long hairs on their leaf-blades 

 are like those of 7\ vulgare in form and arrangement but longer. The 

 culms are hollow and thin-walled. The rachis is non-fragile, but the 

 ear falls off the straw as a whole without disarticulating into separate 

 spikelets. The grains are small, resembling in form and general mealiness 

 those of T. vulgare, and like the latter arc convex on the dorsal side without 

 the prominent ridge found on grains of the Emmer series. 



In A. ovata the culms are 20-35 cm. high and the ears 2-3 cm. lonjj, 

 with 2-5 spikelets, one or two at the base and apex being rudimentary 

 and sterile. The fertile spikelets are 3- to 4-Howered, each ripening one 

 or two grains. 



The empty glumes are convex, inflated, and truncate at the apex, 

 without a keel, but having several prominent lateral nerves, and terminating 

 generally in three or four awns, 2-4 cm. long (i, Fig. 223). The flowering 

 glumes terminate in 2 or 3 short awns, usually less than 2 cm. long. 



A. cylindrica is a taller species with more erect culms 30-60 cm. high, 

 and longer, more slender, cylindrical ears 6-12 cm. long, and composed 

 of 5-10 spikelets (Fig. 223). The axis breaks below the spikelets as in 

 T. Spdta when roughly handled (Figs. 214, 217). The empty 



