No. 515] 



VITALITY OF PINE SEEDS 



681 



the seedlings that appeared were counted on July 

 and July 22, with results as shown in the table below. 



Increased numbers in the later readings are due to de- 

 layed germinations: decreased numbers to failure to 

 emerge or to damping off after emergence. 



It should be noted that the conditions that exist in 

 these serotinous cones are almost ideal for the preserva- 

 tion of the vitality of the seeds. While some exchange 

 of gases is allowed, the spores of fungi and bacteria are 

 effectually excluded; and most important of all, a suffi- 

 cient humidity is maintained to prevent a fatal de- 

 hiscence. That this humidity is due to contact with the 

 moist wood of the live tree is shown by the mechanical 

 opening of the cone through drying when it is removed 

 from the wood, or when the tree dies. This opening, 

 however, is not always either prompt or complete. 



7 This counting was, in my absence, kindly made by Mr. Fred. J. Seaver. 



