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



at once to weak solutions. It immediately became blue when treated 

 with the alkali and became red again when the acid was applied. 

 The chloral-hydrate test here and in all other instances was less 

 definite than in the case with most anthocyanin deposits. Upon its 

 application the red color faded very slowly, until the natural yellow 

 of the glumes became apparent. The red immediately returned when 

 acid was added. There is no reasonable doubt that the color in these 

 barleys is due to anthoc3^anin. 



A naked barley with a violet or. purple pericarp was examined. 

 This color was also readily demonstrated to be anthocyanin. In this 

 instance, as in some others, the pigment was found both in the peri- 

 carp and in the aleurone layer. In the former tissue it was red and 

 in the latter blue. When treated with acid the red was unchanged, 

 of course, while the blue also became red, greatly intensifying the 

 effect. 



In all barleys studied the anthocyanin was always red in the peri- 

 carp and glumes and always blue in the aleurone layer. In other 

 words, the resting condition of the protoplasm was alkaline, while 

 the inert tissue seemed to be in an acid condition. 



A new form of naked barley isolated from an Abyssinian importa- 

 tion gave striking testimony of the taxonomic value of the distinc- 

 tion between the two pigments. This selection has a dense black 

 pericarp. It was absolutely resistant to all concentrations of re- 

 agents, showing the pigment to be melaninlike. As far as the writer 

 can learn, there is no other naked barley of the nutans group in 

 which this pigment occurs, and this botanical form has no published 

 description. 



The last variety studied was Howleum vulgare pallidum coerules- 

 cens. This variety has the peculiar blue color well known upon the 

 market in Californian, Chilean, and similar barleys. The color has 

 been held to be variable by both grain dealers and scientists. Kegel 

 explains its lack of stability by calling it a hybrid form. Examina- 

 tion showed the color to be due to a deposit of anthocyanin in the 

 aleurone layer. This layer was readily changed to red by the appli- 

 cation of acid and was as readily made blue again by the use of alkali. 



The stability of this and other forms was studied in the fields. 

 Anthocyanin seems likely to be found in any plant and in any part 

 of the plant. It seems to appear abnormally in cases of malnutrition 

 and is very likely to occur in conductive tissues that are ceasing to 

 be functional. It has, however, a normal phase in the grain. In 

 certain naked forms its stability is unquestioned, and, to the writer's 

 mind, its variability in coerulescens has been overestimated. The 

 hybrid theory of Eegel in regard to coemlescens becomes untenable 

 when two pigments are admitted. If an intermediate, it could be 

 so only between a white variety and a black one. This is evidently 



