DISTINCTIONS IN CULTIVATED BAELEYS. 25 



lated with the taxonomic groups as to make them of slight use in 

 separating nearly related strains. All the Hanna barleys have long, 

 narrow awns; the zeocrithon and hexastichum forms have short, 

 rather broad awns and the naked barleys excessively broad ones. 

 In the Manchuria group there is some suggestive variation, but it 

 needs the support of other variants to become convincing. 



There is, in addition to tKese rather narrow variations, a still 

 greater difference in length of awn. In these cases an abrupt and 

 conspicuous reduction takes place. There are botanical varieties 

 characterized by very short awns and others in which the glume is 

 merely pointed. Derr (12) secured such a form through crossing. 

 Such variations make a very decided separation from their long- 

 awned relatives. 



The toothing of the awn is subject to many variations, some of 

 which are constant. The distinctions are often merely those of degree. 

 There are forms, especially in the hexastichum and zeocrithon groups, 

 in which the toothing is very profuse and the individual teeth very 

 large. These characters are constant and are inherited, with no more 

 tendency to variation than are other vegetative characters. In the 

 Manchuria-Oderbrucker barley the teeth are numerous, but only 

 average in size, being much smaller than the ones referred to above. 

 The 2-rowed barleys of the Hanna type have fewer and very much 

 smaller teeth than the Manchuria. In still other barleys the awns 

 are smooth. In 1910 the writer isolated from a mixed Hanna barley 

 a form in which the awn was smooth, except for a few small teeth at 

 the tip. In 1911 two plants were secured from an English importa- 

 tion of a seldom-cultivated botanical variety in which the awns are 

 absolutely smooth. Hybrids of this selection upon Manchuria and 

 Bay Brewing sorts show the toothing to be dominant over the absence 

 of teeth. In the second generation smooth awns again appeared. 

 Kegel (22) and others have reported a considerable number of such 

 barleys. 



Although it seems not to have been used by systematists, the rigid- 

 ity of the awn has been found to be serviceable in varietal descrip- 

 tions. From most barleys it is broken rather easily in thrashing, 

 but there are some which will not thrash clean, no matter how much 

 effort be expended. This character is commonly recognized in the 

 California barley, but exists in Mariout, in some of the selections 

 from Odessa, and in numerous others as well. These varieties have 

 been grown at a large number of points and show no inconstancy in 

 this character. 



There is also a difference in the persistence of the awns. There are 

 a few varieties that are almost deciduous. The Primus, for instance, 

 has been observed in a great variety of locations, and it always drops 

 a large percentage of its awns as it ripens. The loss of the awn in 



