1920] JONES— MAPLE SEEDS 129 



for the beginning of germination is the protrusion of the tip of the 

 hypocotyl through the integuments. 



Water and temperature relations 



Fruits were collected at time of shedding and stored at various 

 constant temperatures from o to 40 C. At 25 C. and above 

 fruits were stored in open wire baskets. At 20 C. and below 

 they were stored in loosely covered cans which contained a con- 

 siderable quantity of calcium oxide. The lime facilitated drying 

 at the lower temperatures, besides preventing the accumulation 

 of an excess carbon dioxide pressure about the seeds. By 

 August 26, 1918, all seeds desiccated at 0-40 C. had lost their 



TABLE I 



Life duration of seeds stored at 

 various drying temperatures 



Storage temperature 



Life duration* 



?c° C 



6 days 

 8 



^O 



2* 



22 



20 



20 



10 



' — ^^^ 



49 

 92 









* At 25 C the humidity of the air was consider- 

 ably higher, and drying somewhat slower than at 

 20 C, accounting for increased life duration. 



ability to germinate. In all cases seeds were considered to have 

 lost their viability when 80 per cent failed to germinate when 

 placed on moist filter paper at 30 C, all seeds having either germi- 

 nated or decayed. From o to 35 C. the seeds lost their viability 

 when the water content was reduced to 30-34 per cent. So far 



determined 



C. 



for desiccation do not appear to raise or lower the critical point 

 of water content. At 40 C. death does not seem to be due to 

 desiccation. Seeds turn black in a short time, killing apparently 

 being due to the destructive action of this high temperature. 

 One apparent effect of increasing temperatures (0-35 C.) is the 

 shortening of the desiccation period, no change being evident in 



