Methods in Germination Tests of Coniferous Tree Seeds 73 



germination apparatus, cut open and the number of those show- 

 ing apparently fertile embryos added to the number % already 

 germinated, and in this way the final germination per cent is 

 obtained. By the final germination period is meant, in this paper, 

 the period elapsed between starting the germination test and 

 securing the final germination per cent. 



It is a recognized fact, however, in the practice of making 

 germination tests that final germination per cent is not a true 

 index of the value of the seed for nursery or field sowing except 

 under very unusual conditions. Haack* points this out very clear- 



*Heack: Keimung und Bewertung des Kiefernsamens. Zeitschrift fur 

 Forst und Jagdwesen, 38:462-469. 



ly. There are always a number of seeds germinating after a certain 

 time limit which will not produce healthy, hardy seedlings owing 

 to little known inherent qualities in the seeds or to local con- 

 ditions under which the seeds are to be sown. This is a matter 

 of common knowledge in European practice and may be safely 

 adopted as a maxim in this country. 



The recognition of this principle has led to the establishment 

 of a time limit in germination tests beyond which the germina- 

 tion is considered to be of no value for practical purposes. This 

 time limit will, of course, vary with different species, with the 

 character of the germination apparatus employed, and with the 

 local conditions under which the seed is to be planted. At 

 present it is usually fixed according to the judgment of the one 

 making the tests, based on the results of a number of tests, 

 combined with a careful consideration of the factors mentioned 

 above. Wiebecke**, working at the Eberswalde seed extracting 



**Wiebecke: l>ie Anwendung. neuen Frkennens und Konnens auf die 

 Kiefernsamendarre. Zeitschrift fur Forst und Jagdwesen. 42:355, 356. 



establishment, found that the results from several thousand 

 tests of coniferous tree seeds bore out the opinion. of Haack that 

 this time limit should be set at seven days, thus assuming that 

 all seeds germinating during that period would be of value for 

 field purposes, those germinating later valueless. A filter paper 

 germination apparatus, which will be described later, was used. 

 Bates***, at the Fremont Experiment Station, established this 



*** Rates: Technique of Seed Testing. Proceedings of the Society of 

 American Foresters. 8:134. 



time limit as 25 days for yellow pine, 31 days for lodgepole pine, 

 35 days for Douglas fir for Wyoming use, 21 days for Douglas 



