PLATE XXV. 



A, I'iXL'S llETKKOPHVLLiV.. ]\:i<lial anil taiigontial scctiona of a transverse resin duct; r. d., resin duct ; hi. r., nuihil- 

 lary ray; tr., tracheids of the medullary ray; p., parenchyma cells of the same; r. tr., common traclieids or 

 wood fibers. 

 B-fi, Pixus GLABRA. II, tangential section of a transverse resin duct and ]>arts of three fibers; h.p., bordered ]>it; 

 other letters as above; C~G, tangential soctioiis of mrdnllary r.ays, of which /' is made up of tracheitis only, 

 while D is a " triple " ray. 

 H, Pi.Nis TKDA. Tangential sections of medullary rays in spring and summer wood. 

 Original magnified 500 times, illustrations about ''-'l". 

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