THE IDENTIFICATION OF VARIETIES OF BARLEY. 



11 



The four species, vulgar e, intermedium, distiehon, and deficiens, 

 shown in Plate II, seem best to represent the differences as they exist. 

 It is not to be assumed that this is the only method of separation 

 which might be made on the basis of fertility. Genetically the pointed 

 or rounded nature of the lateral floret may be correlated with the true 

 relationship of the varieties, but it would be practically impossible to 

 use this distinction in the deficiens group. Neither does it fit in with 

 work already done. On the other hand, the species founded upon fer- 

 tility alone require little modification of existing schemes. As has 

 been noted previously, many taxonomists in the past have combined 

 and even confused fertility with density. The work of Kornicke 

 well illustrates this point. As Kornicke is the most widely known of 

 the investigators who have combined the two characters, his scheme 

 is represented graphically in Table I. 



Table I,— Scheme of classification of barley founded upon both fertility and density. 

 [Terms in italic represent Kornicke's major groups.] 



fvery dense. 



B. vuigare. 







(hexastichum . . 



" 





normal 6-rowed... 



[tetrastiehum. 



[dense. 



r polystichum..' 



intermedium 



("dense. 



(.lax. 



[dense 



[very dense 





normal 2-rowed 





[dense. 



jdistichum j 



-— 



1 lax. 





It will be noted that Kornicke's major groups have very little 

 relation to each other. Beaven (1902) remedied this defect to some 

 extent by carrying over zeocriton to designate the dense normal 

 2-rowed, distichon to represent the lax, and decipiens to designate 

 the deficient 2-rowed barley. His grouping, however, was not on 

 equal separations, in that the intermedium and decipiens were sepa- 

 rated further into dense and lax, which separations are parallel 

 Avith his zeocriton, distichon, vuigare {tetrastiehum Kcke.), and 

 hexastichon. Although the system of Beaven was an improvement 

 in a way, it still maintained the objectionable principle of com- 

 bining the characters of density and fertility. 



When the present work was begun it was thought that it w,ould 

 be almost impossible to maintain these well-established distinctions. 

 However, by eliminating the density factor and retaining only the 

 question of fertility, the four species already mentioned were ob- 

 tained. This scheme is graphically represented in Table II. 



