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 barley 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 ereetum 
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 
Short-haired 
24.2 
Hordeum sativum vulgare: 
Manchuria types- 
Long-haired 
22.6 
Short-haired, white 
Short-haired,blue 
aleuron 
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 ^ve 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 
