Methods in Germination Tests of Coniferous Tree Seeds 85 



under the same greenhouse conditions of temperature as stated 

 on page 83, but were given varying amounts of water* per day. 



The seeds receiving the lowest moisture daily showed a 

 marked decrease in final germination, but there is little to choose 

 between the three samples receiving the greater amounts, since 

 the periods elapsing before germination commenced are very 

 close for all three and the final germination per cents vary but 

 slightly. The differences are not marked enough to draw any 

 conclusions with these three, but the longer period elapsing be- 

 fore germination commenced and the lower final germination per 

 cent of No. 2 as compared with No. 3 and the lower final germina- 

 tion per cent of No. 4 as compared with No. 3 suggests that the 

 amount of moisture per day received by No. 3 was probably the 

 optimum, No. 2 receiving not quite enough and No. 4 slightly too 

 much. 



However, these data are offered not in an attempt to establish 

 a rule concerning the optimum moisture requirement, but merely 

 as an illustration of the effect of moisture. Suffice it to say that 

 in germination tests the surface soil should be kept continually 

 moist and never permitted to dry out. 



The method of making germination tests of coniferous seeds 

 given in the following is one which the writer found very satis- 

 factory. 



First, froin the lot of seed to be tested, just as received from 

 the field or storage house, a representative sample is selected. 

 Even though the seed has been cleaned at the time of extraction it 

 is rarely, if ever, entirely free from foreign matter, which neces- 

 sitates further cleaning at the time of testing. This will be ex- 

 plained later. If the lot is large, several pounds are selected at 

 random from various parts of the lot, while if the lot is small 

 (a few pounds), it is included entirely. The quantity selected 

 is thoroughly mixed by hand and then divided into two equal 

 portions, as closely as possibly can be done by the eye. One 

 of these portions is discarded and the other divided in the same 

 manner. This process is repeated until two portions of about 



