268 



BOARD OF AGRICULTURE. 



A later series of experiments by Professor Sachs showed 

 conclusively that the minimum temperatures in the above 

 table are too high. Many observations have lately been 

 made, notably those by Uloth ^ and Kerner,^ by which it 

 appears that the seeds of many plants can germinate at a 

 temperature slightly above that of melting ice. The re- 

 peated examinations lately made in testing seeds indicate 

 that the most favorable temperature for the germination of 

 the seeds of most agricultural plants is to be found between 

 the figures given above in the optimum column. 



The conditions which have now been briefly referred to as 

 essential to germination at all are moisture, warmth, and 

 oxygen; and incidental reference has been made to the 

 amount of moisture, the degree of temperature, and the 

 percentage of oxygen, ascertained to be best for rapid and 

 healthy germination. We pass next to a consideration of 

 a few conditions of normal germination which are dependent, 

 not on the surroundings of the seed, but upon the seed itself. 



1. The Degree of Maturity of Seeds. 



Without devoting too much space to the present views 

 respecting the influence of ripeness upon germination, the 

 results of two experimenters may be stated.^ 



Nowacki, at the close of a long series of observations upon 

 the maturity of wheat, concludes that yellow-ripeness is the 

 best stage ; and with this view many practical writers quoted 

 by Nobbe agree. The observations of Nobbe liimself upon 

 the germinative capacity of ripe and unripe seeds of conifers 

 are instructive. In nearly every case there was distinctly 

 evident that a mean ripeness, which is between a too early 



1 Uloth, Flora, 1871, No. 12. 2 Botan.-Zeitung, 1873, 437. 



8 See Appendix for notes of early views respecting the requisite degree of 

 maturity of seeds. 



