PROPAGATION BY MEANS OF SEEDS AND SPORES 47 



like that shown in Fig. 25. Its flange is made of the required 

 thickness, and it is pressed into the soil until the cap strikes 



FIG. 26. Tracy seed-planter. 



the surface. This is a useful implement in seed-testing. 

 Another device for regulating the depth of sowing, particularly 

 in seed-testing, is the Tracy planter, shown in Fig. 26. It 

 consists of two strips of heavy tin plate about three inches 

 wide, hung on two wire pivots or hinges some two inches long. 

 At their upper edges, and equidistant from either end, the 

 plates are joined by a firm spiral spring, which serves to throw 

 the upper edges apart, and to cause the lower edges to join. 

 The trough is now filled with the required number of seeds, 

 and is then inserted into the earth to a given depth, when 

 the fingers push inward on 

 the springs and the trough 

 opens and delivers the 

 seeds. 



Delicate seeds, sown out 

 of doors, should be given 

 a very accessible location, 

 because they will need 

 constant watching in dry 

 weather and during heavy 

 rains. A border along a 

 wall is a favorite site for 

 a seed-bed. A French 

 method of preparing such a 

 bed is shown in Fig. 27 



(after Mottet). FIG. 27. Seed-border. 



