74 Forest Club Annual 



fir for Colorado use and 22 days for Engelmann spruce by tests 

 of ten or more samples of each species (each sample containing 

 500 seeds), the time limit for each sample being assumed to 

 have expired when the germination for any one day dropped 

 below two seedlings and the germination on the next day did 

 not exceed two. The seeds were germinated in pure sand and 

 under greenhouse conditions. The results are, of course, as 

 Bates points out, only applicable for the central Rocky Mountains. 

 On stating the case briefly as shown by the work of these two 

 investigators, the time limit is set at the point when the germina- 

 tion of seeds becomes negligible for practical purposes such as a 

 field or nursery sowing. 



This time limit is now commonly called in America the 

 germinative energy period or germinative force period, while 

 tne percentage of germination obtained at the expiration of the 

 period is termed germinative energy or germinative force.* 



*Lovejoy: A Suggestion for Securing Better Professional Terminology. 

 Forestry Quarterly, 12:2. 



These terms do not seem to be clear in so far as they do not 

 express exactly what is meant, and furthermore, there is room 

 for question as to whether they are correctly applied. Wiebecke** 



** Wiebecke: Anwendung neuen Erkennens auf die Kiefernsamendarre. 

 Zeitschrift fur Forst und Jaguwesen. 42:355, 356. 



uses germinative energy (Keimenergie) in the same sense as 

 germinative force seems to be commonly accepted in America, 

 but uses (jcnnmativc force (Keimkraft) to denote final germina- 

 tion. Lorey***, on the other side, defines the germinative force 



***Jjorey: Handbuch der Forstwissenschaft. 2:106. 



as the germinative per cent combined with the "germinative 

 energy". Wagner 1 considers the germinative energy to be the 

 force with which the seed breaks through the surface of the 

 soil. Mayr 2 seems to view germinative energy as the rapidity 



iWagner and 7Mayr: \Valdbau auf naturwissensehaftlirhen Grund- 

 lage. 371. 



of germination. The case reduces itself to this : Some investiga- 

 tors use the terms germinative energy and germinative force in- 

 terchangeably for the germination per cent at the expiration of 

 a certain limited time ; again germinative force is considered to 

 be the combination of energy of germination and the germination 

 per cent in one instance, and used to denote final germination in 



