PLATE XXII. 



A, I'INOS ECHINATA. Cross section of two rings; sp. >., springwood; . w., suramerwood. . 



/(, Pisus TALUSTRIS. Cross section of a very narrow ring. Of the two medullary rays one is cut through a n>w of 



parenchyma, the other through a row of tracheids. 



C and I), Piwrs GLABRA. Radial sections ; m. r., medullary rays ; tr., tracheids of the medullary rays ; p., parenchyma 

 of the same; . p., simple pits leading from the parenchyma to the neighboring tracheids or common fibers 

 c. tr.; b.p., bordered pit. The ray at C is made up of tracheids only. 

 K, PINUS PALUSTRIS. Radial section; lettering as in D. 



Originals magnified: A, a ? s , the rest *f a ; illustrations : A, ^, the rest ^f^. 

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