Nov. 26. 192 1 Storage of Coniferous Tree Seed 491 



cloth bag, cloth bag oiled. This is somewhat interesting. Small lots of 

 seed of a few pounds are perhaps stored more often in a cloth bag than 

 in any other container. This study indicates that on the average an 

 ordinary heavy manila type of paper bag would, if tied at the top, be 

 superior to the cloth bag. If the paper bag can be treated with a coat 

 of paraffin, it will be still better. In fact the germination percentage of 

 Pinus contorta in the paraffined paper bag was slightly greater than, and 

 of P. ponderosa nearly equal to, that of the sealed bottle after one year's 

 storage. The oiled cloth bag is decidedly inferior. This is much less 

 pronounced with P. ponderosa than with the other species. Whether 

 the general inferiority of this container is due to penetration of the seed 

 coat by the oil and consequent injury of the embryo, to the prevention 

 of access of water to the embryo when the seed was sown, or to some 

 other cause is unknown. Regardless of the reason, the truth is evident 

 that such a container should be avoided in storing any of these seeds. 



The superiority of the bottled seeds over those in other containers is in 

 all probability due to the almost complete suspension of physiological 

 activity by the seed thus stored. (This was not verified by any experi- 

 ruents undertaken in connection with this study.) The two conditions 

 essential for such activity are warmth and moisture. The seed in the 

 bottles was of course exposed to high enough temperature to induce 

 respiration, but the necessary amount of moisture for any great degree 

 of activity was not present. Such moisture as was present in the seed 

 or bottled air could not be increased by additions from without. On 

 the other hand, the seed in the other containers was intermittently sub- 

 jected to both temperature and atmospheric moisture conditions sufficient 

 at times to induce rather active respiration. Such respiration can be 

 carried on only by using up food material stored in the seed itself, with 

 the consequent gradual weakening of its germinative ability. The seed 

 stored in the paraffined paper bag and the plain paper bag were, it is 

 believed, less subject to changes of atmospheric moisture than that 

 stored in the ordinary cloth bag. The rate of deterioration was in 

 consequence less rapid. 



It is quite generally held by forest tree seed investigators that the 

 true criterion of the quality of seed is not alone its germinative ability 

 or viability (germination percentage) but rather this germinative ability 

 in conjunction with germinative power or energy. Rapidity of germina- 

 tion (the germination percentage at the end of a certain period of time) 

 is the measure of this germinative energy. This period is measured from 

 the date of sowing the seed through the time that germination is pro- 

 ceeding steadily and rapidly and at the end of which it starts to fall off 

 rather abruptly. If the progress of germination is plotted and curved, 

 the point at which the curve begins to fall off rather abruptly and flatten 

 out will represent the number of days which should be selected for that 

 species. Now, the quality of the seed will be determined by the mean 

 of the germination at the end of this period and the final germination 

 percentage. 



By final genninative percentage is not meant here the absolute final 

 but rather that at the end of a reasonable period. Accepting this hypoth- 

 esis, Table II was prepared, and the curves in figure i were drawn from 

 it. They represent the quality of each species of seed stored in each 

 container at the end of one, two, three, and five years. The periods 



