24 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



Aside from the observations upon established forms, it has been 

 the fortune of the writer to isolate a number of which there seem 

 to be no published descriptions. These all came from Abj^ssinian 

 barleys, and, as the work is not yet completed, only a general indi- 

 cation of the results need be given here. The group of 2-rowed 

 barleys with rudimentary florets seems much larger than has been 

 previously thought. They vary from the wide zeocrithonlike types 

 to narrow nutanslike forms and through a series of colors and com- 

 binations of colors. In barleys received from the same region there 

 is a group with a curious irregular", yet heritable, habit of floret 

 abortion. In the ripened spike the spikelets are normal at the base 

 and for a varying distance toward the tip. The upper portion 

 usually reduces suddenly to a 2-rowed form. In this case the lateral 

 spikelets are not merely sterile, but are reduced to only the outer 

 glumes and the rachilla, the floret having disappeared entirely. The 

 spikes are found to present these modifications even when the head 

 first emerges from the boot. The actual time of the reduction has 

 not been determined, but it is so early that no scar is present, indi- 

 cating that the floret never started to develop. 



THE EMPTY, OR OUTER, GLUMES. 



The outer glumes present but two phases. They are usually nar- 

 rowly lanceolate, but in rare forms are ovate lanceolate. In the 

 latter case they generally bear moderately long awns. A few inter- 

 mediates are formed by combinations in which only certain ones 

 instead of all the normal outer glumes are replaced by ovate-lanceo- 

 late ones. In this investigation, while numerous ovate-lanceolate 

 selections have been made, there has been nothing added to the 

 information already at hand. 



THE FLOWERING GLUMES. 



Two of the variable features of the flowering glume are treated 

 elsewhere. The toothing of the nerves is considered with the rest 

 of the Svalof system under a later heading. The color of the glumes 

 is taken up with the color of the other plant organs in the general 

 discussion of pigmentation. Most of the remaining variable points 

 of structure in the flowering glume are to be found in its terminal 

 appendages, which are usually awns, but may be trifurcate hoods, 

 in the nature of its base, and in its adherence or nonadherence to the 

 pericarp. 



AWNS. 



The dimensions of the awns are naturally their most apparent 

 variable features. There are marked varietal differences in both 

 length and breadth of awns, but, unfortunately, they are so corre- 



