THE IDENTIFICATION OF VARIETIES OF BARLEY. 13 



uncommon, and deficient barleys which show intergradations toward 

 the normal 2-rowed are rare indeed. 



In the 6-rowed barleys all awnless forms are thrown into inter- 

 medium. The awnless character is most probably of hybrid origin, 

 and in all 6-rowed awnless varieties now known there is a tendency 

 in some strains to produce short awns on the central spikelets when 

 grown under especially favorable conditions, indicating a direct rela- 

 tionship with intermedium. It may be found necessary to include 

 awnless sorts under Hordeum. vulgare as well, but at present it seems 

 better to list these forms with the intermedium. 



Of the varieties and subvarieties which follow, a large number are 

 of hybrid origin. The species intermedium probably consists entirely 

 of hybrid varieties. In the beginning it was attempted to separate 

 the known hybrid varieties from those occurring naturally. How- 

 ever, there seems no good reason for such a distinction, for many of 

 the varieties which are not known to be hybrid probably have arisen 

 from accidental crossing. 



For example, the variety horsfordianum was named for a Mr. 

 Horsford in Vermont, who crossed a Nepal (6-rowed hooded naked) 

 on a 6-rowed bearded hulled and obtained a 6-rowed hooded hulled. 

 This variety is grown extensively in the United States and is abso- 

 lutely constant. It is inconceivable that all barley of this descrip- 

 tion in this country and elsewhere came from Mr. Horsforcl's cross. 

 The Nepal has been grown in India alongside of hulled varieties for 

 centuries, and the cross must have occurred time and again naturally, 

 despite the fact that barley is one of the most closely fertilized of 

 plants. It is a strange coincidence that the only natural hybrid that 

 has occurred in the nursery in the six years of this investigation was 

 between the Nepal and a 6-rowed bearded hulled variety, from the 

 progeny of which a Horsford type has been isolated. 



In describing varieties, fertility having been used as a specific dis- 

 tinction, there remain hulled or naked kernels, awned (including 

 awnless) or hooded lemmas in the central spikelet, and white (includ- 

 ing blue and purple) or black color as major distinctions. The first 

 two of these characters, with the variation in width of the outer 

 glumes later spoken of in the discussion of subvarieties, are shown 

 in Plate III. The regularity of the gradation in differences be- 

 tween the varieties in each group is sufficient to excite the suspi- 

 cion of the taxonomist, because such uniformity is not common in 

 nature. Ordinarily, variations do not occur in a closely graded series. 

 Neither did they in barley at first, but continued crossing, natural and 

 artificial, has slowly filled the gaps. 



Hordeum , vulgare trifurcatwn, for example, at first stood off 

 clearly as the trifurcate naked 6-rowed barley. Then horsfordianum 

 was produced and there were two trifurcate 6-rowed sorts, one hulled 



