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PLANTS AND MAN 



elements as well as by the plane in which the wood is cut. Spring 

 wood has an abundance of large thin walled conducting vessels 

 and few fibers (fig. 176) while summer wood has fewer vessels 

 and many more fibers and other supporting elements. Hence the 

 spring wood is more porous and absorbent of stains than the 



Fig. 176. — A Dicot stem has more and larger vessels, fewer fibers, in the 

 spring wood; the summer wood by contrast seems denser, thus producing the 

 annual ring. 



denser summer wood. Grain is also influenced by the texture of 

 the wood, as is seen in straight grained pine wood, the twisted 

 grain of many hardwoods, and the swirling pattern found around 

 knots. 



When the fibers are found in the pericycle or the phloem they 

 form tough strands running lengthwise of the stem. Such bast 



4 



