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POPULAR SCIENCE MONTHLY. 



this fact the plant is sometimes recognized as the "Arizona 

 candle." 



Just beneath the epidermis and alternating with the spiny 

 ribs are strong ligneous fascicles. These fascicles are of the same 

 number as the ribs, and serve as a support for the soft paren- 

 chyma tissue which constitutes the great bulk of the plant. 



The fascicles are not unlike huge fish poles, twenty to forty 

 feet long and from one to three inches in diameter, flattened 

 radially as relates to their position of growth. This woody por- 

 tion endures long after the other parts of the plant have decayed 

 and is popularly known as the skeleton. During the growth, of 



A CACTUS FOREST. 



the plant the fascicles increase in size each year by the addition 

 of a woody layer to their outer surf ace, in the same manner as the 

 oak and maple add their annual layers. The layers of growth 

 forming the older fascicles are very close together, sometimes a 

 hundred being crowded into less than an inch of space. 



This portion of the plant is of great value to both Indians and 

 Mexicans, as it not only serves as firewood but is extensively 

 utilized in both fence and house building. When cut to requisite 

 length it makes excellent pickets, and throughout its entire range 

 the dirt roofs of the adobe houses are supported by the long, 

 strong fascicles. 



We find by counting the layers of growth that many of the 



