FOREST TREE SEED AND SEED COLLECTING 



119 



somewhat similar to the Geneva seed germinator. It consists of 

 a shallow impervious pan, usually made of zinc. Glass rods or 

 perforated zinc plates are supported an inch or less above fresh 

 water previously placed in the pan. Circular woolen cloths, 

 cotton cloths and blotting papers are placed one above the other 

 on the rods or plates. The sample of seed is placed on the paper 

 and the whole covered with a glass plate so that full daylight has 

 access to the seed. Strips of flannel or other wicks hang down 

 from the woolen cloths into the water. It is recommended that 

 the water be heated to a temperature of 97 F. every 3 hours 

 during the day. This raises the temperature under the glass cover 

 to from 78 to 82 F. 



This apparatus has been in 

 use for many years in many 

 seed - testing laboratories in 

 Europe. 



Haack recommends that in 

 all forms of apparatus where 

 the seed lies on bibulous paper 

 and secures its moisture by 

 capillary action, the free water 

 should be 1.2 inches below 

 the paper, and when flannel is 

 used but 0.6 inch below. 



29. THE GERMINATING 

 OVEN. The germinating 

 oven is necessary in all exten- 

 sive germination tests when 

 hothouse facilities are not 

 available. The standard oven 

 is double walled and made of 

 copper. A water space is 



FIG. 23. Standard seed-germinating 

 oven, a, Sheet-iron base; 6, burner; 

 c, ventilators; d, gas exit; e, door; 

 /, shelves; g, asbestos cover; h, open- 

 ings into chamber; i, therm o-regula- 

 tor; j, openings into water jacket; k, 

 gas entrance tube. 



afforded by the two walls. 

 The outer surface of the oven 

 is usually covered with felt to 

 lessen the loss of heat by radiation. The chamber is heated by 

 gas or electricity and the temperature controlled by a thermo- 

 regulator. Openings into the oven control the exit and entrance 

 of gases. The seed is placed between moist blotters or on porous 

 germinating plates and arranged on the shelves within the oven. 



