drushel] SEED WITH A SELF-PLANTING DEVICE 



193 



Figure 2 shows the result of immersing the seed in figure 1 in 

 water eight minutes. On account of the position of the upper 

 half of the style (1 fig. 1) in the untwisting process the greater 

 force is downward, driving the seed into the soil. 



If the seed partly planted becomes dry, the style takes on the 



A 



~~| 



These photographs were reduced three-fifths from pen and ink draw- 

 ings of the seed x 5. As they stand they are the original x 2. 



spiral form. But the barbs on the seed resist the tendency to 

 be pulled out of the soil. Figure 3 shows the effect of exposing 

 the seed in figure 2 to dry air for five minutes. 



An experimental planting showed a penetration into ordinary 

 soil to a depth of more than twice the length of the seed in ten 

 days under alternating moist and dry conditions. 



