16 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



The summary of leaf measurements of 316 pedigreed selections 

 in Table IV shows that the common taxonomic groups, based upon 

 spike characters, are correlated in the nature of their leaf growth. 



Table IV. — Summary of measurements of the width and length of oarley leaves 

 made at St. Paul, Minn., in 1911, arranged according to the common taxo- 

 nomic groups. 



Group. 



Number 



of 

 strains. 



Leaf width. 



Leaf length. 



Greatest. 



Least. 



Average. 



Greatest. 



Least. 



Average. 



Hordeum sativum erectum 



Hordeum sativum nutans: 



11 



67 

 18 



49 



85 



34 

 23 

 29 



Mm. 



17 



14 

 18 



18 

 20 



19 

 19 

 19 



Mm. 

 13 



9 

 10 



13 

 15 



14 

 13 

 10 



Mm. 

 14.0 



11.4 

 13.6 



16.1 

 17.7 



16.8 

 17.0 

 15.4 



Cm. 

 26 



27 



28 



25 



26 



25 

 27 

 26 



Cm. 

 22 



20 

 20 



20 

 22 



21 

 22 

 19 



Cm. 

 23.9 



23.0 





24.2 



Hordeum sativum vulgare: 

 Manchuria types — 



22.6 



Short-haired, white 

 Short-haired, blue 



23.7 

 23.3 



Russian types... 



Hordeum sativum hexastichum . 



23.7 

 22.2 



NUMBER OF LEAVES. 



The number of leaves, excluding, of course, those "formed before 

 the appearance of the shoots, is the same note as the number of elon- 

 gated internodes in the culm. The number of leaves above the basal 

 rosette is a variable, but at the same time rarely a useful distinction 

 in breeding. Strains may be found which are very different, but 

 usually they are not closely related. Thus, in the variety Hannchen 

 the number often drops to three and seldom goes above five. In the 

 selection of Hordeum sativum hexastichum the number rarely falls 

 as low as five and is usually six or seven. This distinction, however, 

 is not necessary to separate these forms. In each of several hundred 

 Manchuria selections the number of leaves per culm fell upon either 

 four or five, giving no opportunity for separation. 



THE DENSITY OF THE SPIKE. 



The writer is inclined to place even more importance upon the 

 density of the spike than has been the tendency of many barley 

 breeders. Aside from its finer distinctions, some of the effects at- 

 tributed to other characters are in reality due to the length of the 

 internode of the rachis. Most investigators have attributed the dif- 

 ference between Hordeum sativum vulgare (tetrastichum) and Hor- 

 deum sativum hexastichum to a difference in fertility. They have 

 considered that in Hordeum sativum vulgare the side florets are more 

 reduced than in Hordeum sativum hexastichum. This supposition is 

 not borne out by the facts. In the Hordeum sativum hexastichum the 

 central row is as favored in nutrition as it is in the Hordeum sativum 



