34 BULLETIN 131, U. S. DEPARTMENT OF AGRICULTURE. 
which each awn was marked with two parallel stripes of red extend- 
ing from its base to its tip, and other spikes in which the same stripes 
were deep purple. When examined in the laboratory, the color 
proved to be two bright-red stripes in the epidermis, below which 
were two chlorophyll-bearing parenchyma areas running the full 
length of the awn. As long as the chlorophyll was present the color 
effect was deep purple, but as soon as this disappeared it was light 
red. 
SUMMARY. 
While all lesser distinctions must be based upon the broader 
groups and no study of a cereal can omit its classification, the plant 
characters useful in taxonomic work and the ones most useful in 
plant breeding are far from being the same. Plant breeding is con- 
cerned with minute differences. The broad taxonomic divisions are 
serviceable only as groups. The problem of the nursery is not to 
separate a 6-rowed Manchuria from a 2-rowed Hanna barley, but 
to detect a variant in a plat of Manchuria. 
Strains are often shown to be distinct in early growth by their rate 
of development. All barleys rush through the early stages very 
rapidly, and a selection that is one or two days earlier than a second 
is very dissimilar in appearance on a given date. 
Leaf production is, in some ways, a varietal character. In some 
varieties the third leaf appears in three days after the second, while 
in others it occurs six days later. In the production of the fourth 
leaf even a greater range exists. 
In some strains the first tiller appears decidedly later than the 
fourth leaf. In others it appears earlier. In some the tillers are 
all produced within a short time; in others the process is extended 
over several days. 
The emergence of the awn is an extremely important note, as it 
occurs at a time in the life of the plant when such an observation is 
of great value. The development is usually normal at this time, as 
hot weather and drought have ordinarily not yet had any effect. 
The emergence of the awn has been found to be far more accurate 
and more easily obtained than the date of heading. The precocity 
of the strain at the time of the emergence of the awn is a heritable 
character. 
The date of ripening is, unfortunately, often influenced by season 
and, while a valuable character, is less dependable than the emergence 
of the awns. 
A comparison of the development during all stages serves to reveal 
many differences not apparent when each stage is taken separately. 
The length of the culm is of use as a local breeding note, but the 
variations are not parallel when strains are planted in totally dif- 
