NOTES ON THE BISHOP PINE 



899 



are obtained. In the case of the Humboldt seed r = — .283 ± .023 

 indicating a week negative correlation. This means that there is a 

 slight tendency for the percentage of survival to decrease as the age 

 of the seed increases. The Monterey seed shows a much stronger ten- 

 dency in the opposite direction inasmuch as r = .927 ±: .035 indicating 

 that for this seed the percentage of survival of those ivhich germinate 

 increases with the increase in time of retention in the cone. The 

 above correlations are evident when the values are plotted on cross 

 section paper. The reasons for this difference in the two lots of seed 

 are interesting subjects for speculation. Climatic differences of the 

 two localities during the formation and retention of the seed may have 

 had an influence but many other factors probably had something to do 

 with it. 



Table 5. — Comparative Loss of Bishop Pine Seedlings from Damping Off, 

 Drought, and Other Causes^ 



" Seed beds in both cases were treated after sowing with weak solution of 

 sulphuric acid. (0.1 fluid ounce per square foot of seed bed area) to check early 

 damping off. Total loss was probably slightly in excess of the figures as some 

 seedlings may have disappeared between dates on which records were made. 



Table 5 indicates the comparative loss of seedlings during the sum- 

 mer from damping ofif, drouth, and other causes. It is interesting to 

 note that the seed from the young trees snows a strong negative corre- 

 lation between age and loss of seedlings (r = .755 ± .162) while the 

 seed from the older trees shows almost as strong a correlation in the 

 opposite direction (r^.608 ± .159). 



