108 



those projecting from the outer and lower side of the first and 

 largest pair of secondaries. When there is a narrow margin 

 bordering these veins, the tertiaries proceeding from them are not 

 very strongly developed ; but when this margin is wide, they are 

 very strong. Further, when one side is wider than the other the 

 tertiaries of the wider margin are the more strongly developed. 



Joining the tertiaries are the quaternaries which also exhibit a 

 tendency to form quadrangular areolae. These, particularly when 

 the tertiaries are strong, may be quite marked, but as a rule they 

 are rather weak. 



The nervation may now be briefly described as pinnate and 

 camptodrome, with the two lowest secondaries very much larger 

 than any of the others, while the tertiaries and quaternaries tend to 

 form quadrangular areolae. 



Finally, it may be noted that the facts here presented in regard 

 to the form and venation of the leaves studied tend to show that 

 the practice in vogue among paleobotanists of placing more 

 emphasis upon the venation, for purposes of identification, than 

 upon the form, is a sound one, based upon an appreciation of the 

 more constant characteristics of the former. 



THE VITALITY OF PINE SEED IN SERO- 

 TINOUS CONES 



By J. C. Blumer 



It has long been observed by naturalists that the cones of the 

 group of pines known as jack pines, and some others, often carried 

 closed cones upon their branches for many years. As has been 

 observed for Pinus attenuata by John Muir and others, this sero- 

 tinous character may be a potent factor in producing the aggres- 

 sive restocking of forest land that has been burned over, charac- 

 teristic of several such species, a fact of importance in forestry as 

 well as ecology. 



In the southwest, this group of pines is represented by P. 

 cliihiialmana, and it has the same habit of carrying aged cones. 

 One instance is on record in which a cone belonged to a node 



