DISTINCTIONS IN CULTIVATED BARLEYS. 31 



tion to generation. In other cases the color appears intermittently 

 or sporadically in strains and tissues ordinarily free from pigments. 

 This erratic behavior, coupled with the fact that white, brown, 

 black, violet, purple, amber, and blue-gray have been used in various 

 classifications, led the writer to make a study of the pigmentation of 

 barley. Since the colors in the seed seemed to be more numerous and 

 less variable than in the other parts of the plant, the grain was used 

 as the basis for the investigation. 



The technic was adapted from that used by Mann (18) in his 

 identification and location of the pigments in the cowpea. The 

 grains were "first examined by sectioning them dry. This avoided 

 any modification such as might easily come from the action of solv- 

 ents in an embedding process, or even from water if a freezing 

 method were used. The hand sections were equally as satisfactory 

 as those made with a microtome, as the areas in question were readily 

 defined and the colors more easily seen in moderately thick sections 

 than in very thin ones. The reagents most extensively employed 

 were caustic potash, hydrochloric acid, and chloral hydrate. The 

 sections were placed dry upon a microscope slide underneath a seven- 

 eighths-inch cover glass, held in place by a drop of paraffin on either 

 side. The reagents were drawn beneath the cover glass by means of 

 blotting paper and their action watched through the microscope. 

 Two per cent solutions of the acid and of the alkali and a saturated 

 aqueous solution of chloral hydrate were used in these tests. If the 

 pigment showed no change within a few minutes, the reagents were 

 allowed to remain upon the section for some hours. In such cases, 

 larger pieces were also placed in small vials containing 15 per cent 

 solutions and examined at the end of 24 hours. 



It soon became apparent that there were two pigments in barley. 

 One was readily affected by the weak solutions, and from the nature 

 of its reaction was undoubtedly anthocyanin, which occurs widely in 

 the plant kingdom in both its red, or acid, and its blue, or alkaline, 

 form. The other resisted even prolonged soaking in the more con- 

 centrated solutions and was probably a melaninlike substance. 



The first varieties studied were those in which the adhering glumes 

 were black. No change was effected by either the weak reagents or 

 the prolonged soaking in concentrated solutions. The black did 

 indeed become a brown, but this was most probably due to the dis- 

 tention of the pigment-containing tissues attendant upon the absorp- 

 tion of water. As a considerable number of varieties with black 

 glumes were tested and as the results were uniformly the same, it 

 would seem that a black or brown pigment in the glumes may be 

 attributed to a melaninlike compound. 



A number of Abyssinian varieties with purple glumes were sec- 

 tioned and treated with the reagents. The purple color responded 



