110 



cones thence backward as far as found. Out of a total number 

 of 3,000 seeds less than 10 years old, germinated in the labora- 

 tory under varying conditions, 928, or 31 per cent., proved vital. 

 Out of 3,000 seeds from 10 to 30 years old, 1,346, or 40 per 

 cent., were found to have preserved their vitality. Under the 

 most favorable laboratory conditions the younger seed germinated 

 57 per cent., and the older 67 per cent. Six hundred additional 

 seeds of the same lots were tested in soil, and they gave similar 

 results. At Halsey, Nebraska, in nursery tests made by W. H. 

 Mast, the younger seed produced 28 per cent., the older 47 per 

 cent, of seedlings. At Pasadena, California, also in the nursery, 

 T. P. Lukens obtained figures almost identical ; viz., 27 per cent, 

 for the younger, 45 per cent, for the older. At Washington, the 

 older seeds only were tested in sand flats kept outdoors in occa- 

 sional freezing temperatures. The following spring the result 

 was a crop of seedlings amounting to 64 per cent, of the number 

 of seeds planted. 



The uniformly higher figures for the older seed does not mean 

 that the seed improved with age instead of deteriorating, but 

 simply that it was seed of better quality and that it probably lost 

 little, if any, of its vitality. It was noted at the time of testing 

 that the younger seed was less well filled, and lighter in both 

 weight and color. In cutting open 400 seeds, it was found that 

 only 53 per cent, of this was filled, as against 73 per cent, of the 

 old seed. The cause did not lie in the direction suggested by a 

 case reported by G. E. Tower,* in which the same species in the 

 same state exhibits marked differences in the time of opening its 

 cones according to the soil on which it grows. For all the seed 

 came from the same stand of trees on the same kind of soil. It 

 is possible that the younger seed carne from younger trees, 

 although, as nearly as could be learned, both lots came from the 

 same trees. If the latter is true, the most likely cause would be 

 the unfavorable character of the seasons producing the inferior 

 seed, which might include both weather conditions and parasitic 

 attack. However this may be, there is no longer any doubt as 

 to the longevity of seeds held in serotinous cones. 



* Proc. Soc. Am. Foresters, IV, No. i. 



