84 



Forest Club Annual 



A blotter test of the same material gave a final germination 

 of 75 per cent in 21 days. 



The covering of y 2 inch in the experiments given above was 

 certainly too much. In the course of the experiments it was 

 noticed that the seedlings had considerable difficulty in releasing 

 their seed caps from the soil, in one instance three days being 

 required, while in another the seedling died in five days through 

 inability to free its cap. Only three seedlings appeared at the 

 soil surface from those seeds covered to a depth of three-fourths 

 inch, but these could not release their seed caps and speedily 

 died. The difference in final germination seems to be entirely 

 too marked between those seeds covered to a depth of ^4 inch 

 and* those covered to their own depth (about y% inch), par- 

 ticularly in view of the results obtained by Bates and Somer- 

 ville. A repetition of the first part of this experiment with the 

 same seed in pure sand a year later gave a final germination of 

 76 per cent for seeds covered to their own depth (about ^g inch) 

 and of 88 per cent for seeds covered to a depth of l /^ inch. In 

 this experiment the final germination decreases directly with the 

 increase in depth of covering and the period before the first seed- 

 ling appears increases directly. 



Generally, it may be stated that coniferous seed may be 

 covered to their own depth or to ]/\ inch in sand tests ; the latter 

 depth will probably be preferable, since with the deeper covering 

 there is less danger of exposing the seed through washing off of 

 the soil when surface watering is applied. 



The amount of moisture in the soil used is another important 

 factor in the germination of seeds since either too much or too 

 little will retard germination. Samples of Pinus ponderosa seed, 

 collected at Maine, Arizona in the fall of 1909, were sown in a 

 half and half mixture of sand and loam at the same time and 



