No. 448.] NORTH AMERICAN CONIFERALES. 263 



are also present, but among the Taxacese, while generally pres- 

 ent, they are occasionally wanting as in Tcr- 

 reya taxifolia and T. nucifera or 66.6 of the 

 investigated species of that genus. Nowhere 

 else among the Coniferales do we find such a 

 feature until we reach the genus Pinus, the 

 second and higher section of which is invari- 

 ably characterized by their absence, thus pre- 

 senting an exceptional feature to the extent 

 of 68.3 of that genus. That such absence 

 represents a process of obliteration conform- 

 able to De Bary's law cannot be doubted, 

 while the sporadic recurrence of this feature j|l 

 in often widely separated genera, or in partic- ;> 

 ular species of a given genus, must be held to |! 



have a more or less direct bearing upon the ^ ' 



general course of development. This is em- ^ R3)j|37"^37cron'^lhowS 

 phasized by the observation that in Larix the bordered pits on the 

 americana and leptolepis as also in Picea Tp^ng wood'^'' x 2!. ' ' 

 bicolor, there is a more or less pronounced 

 tendency to an obliteration which is never fully developed. This 

 is expressed in the somewhat remote position of the pits and 

 V./ 'I'l their 



ders them obscu 

 difficult to disco 



