26 



PRINCIPLES OF PLANT CULTURE 



ward, the hook often fails to catch the seed-case, as in D, 

 and so the plantlet emerges from the soil without freeing 

 itself from the seed-case and is hampered for a time. This 

 provision is peculiar to the pumpkin family, to which the 

 pumpkin, squash, cucumber and melon belong, though 



Fio. 7. — Germination in respect to the seed-case. Showing nature's 

 provision to enable the pumpldn plantlet to escape from the seed-case. 

 In B, the hook on the hypocotyl is attached to the lower half of the 

 seed-case. A shows the same after germination is farther advanced. 

 A fiilly germinated pumpkin plantlet is shown in Fig. 8. 



other provisions which accomplish the same end are found 

 in a few other families, but many plants are considerably 

 held back by the seed-case during germination. 



42. Seeds of the pumpkin family should be planted 

 flatwise, rather than edgewise or endwise, since in this posi- 

 tion they most readily free themselves from the seed-case. 



43. Some plantlets need help to burst the seed-cases. — 

 In many seeds having hard and strong seed-cases, as the 

 walnut, butternut and hickory-nut and the pits of the 

 plum, peach and cherry, the enlarging plantlet is often 



