97 



They are colorless, or of a pale yellowish tint, and turn black upon immer- 

 sion in alcohol, the rest of the beet remaining colorless. The spots are com- 

 posed entirely of parenchyma tissue, the cells having fine delicate walls. 

 The cf-lls, in the specimens examined, measured .03 to .075 mm. in diame- 

 ter, while the cells of the adjoining parenchyma measured .15 to .25 mm. in 

 diameter. The measurements were taken in transverse sections of the root. 

 No parasitic organism, either animal or vegetabi*', was found associated 

 with them, and no explanation of their presence is known. 



The scabs, discoloration, and water-core spots do not seem to affect the 

 size of the beets, as they are oftener found in medium and large beets than 

 in smaller ones. The effect of their influence on the sugar content is not 

 known. 



Plant zones of Arizona. By D. T. McDougal. 

 [abstract.] 



The author, while collecting plants in Arizona during May to October, 

 1891, for the Botanical Division of the U. S. Department of Agriculture, 

 made a series of observations resulting in additional data on a biological 

 survey of the San Francisco Mountains made by Dr. C. H. Merriam in the 

 previous year. 



The feasibility of the correlation of the life forms of this region into the 

 Alpine, Timberline, Hudsonian, Canadian, Pine, Pinon and Desert Z mes 

 was recognized. Detailed notes of the occurrence of plants peculiar to 

 each zone, were made, and the bounding lines of each were carried south- 

 ward through the Mogollon, Graham and Chiricahua mountains, and ovex 

 the edge of the Colorado Plateau into the Verdi Touti, Salt and Gila basins 

 to the Mexican boundary. 



Relation of available enzym in the seed to growth of the plant. By 

 J. C. Arthur. 



The potato tuber as a means of transmitting energy. By J. C. Arthur 



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