FOREST TREE SEED AND SEED COLLECTING 



117 



It is one of the best of the porous plate germinators and consists 

 of a dish made of blue crystal glass, 8 inches in diameter and 

 l inches high, resting on four short legs. A glass tube in the 

 center of the dish permits the entrance of air from below during 

 the test. The porous plate is 6 inches in diameter and f inch 

 high. It has 100 small depressions on its upper face for the re- 

 ception of the seeds. A blue crystal glass bell jar 5 inches in 

 diameter with an opening in the top for the exit of air fits into a 

 groove on the upper face of the plate and covers the seeds. In 

 making a germination test, 100 seeds are placed in the depressions 

 on the plate and covered with the bell jar. Water is poured into 

 the dish until it rises two-thirds the height of the porous plate. 

 It reaches the seeds by soaking through the plate. As fast as the 

 seeds germinate they are removed and counted (Fig. 20). 



FIG. 20. Cross section of Stumer's germinating apparatus. 



a. Impervious dish. d. Opening in cover. 



b. Porous plate. c. Opening in impervious dish. 



c. Cover. 



28. Germination Tests Between Strips of Cotton Cloth or Flan- 

 nel. Various forms of apparatus for making germination tests 

 are in use in which the seed is placed between pieces of cloth 

 kept continually moist by water conveyed to them by capillary 

 action. 



When but a small number of seeds are tested the flask method 

 is useful because of its simplicity A moderately wide-mouthed 

 flask is partially filled with water. Two strips of flannel are 

 suspended in the flask, one strip folded to hold the seed 1 or 2 

 inches above the water and the other reaching into the water 



