FLOWERS, FRUITS AKD SEEDS. 79 



seeds of the common Field Poppy, which are a million of 

 times less in bulk. 



Neither has there heen as yet discovered any peculiar 

 property of seeds that would make those possessing it 

 insensible to the influence of surrounding elements and 

 conditions. It might readily be supposed, upon general 

 principles, that seeds containing a large amount of oil 

 would be far less likely to be affected 

 by moisture, dry ness, or even a low 

 temperature, than those of an opposite 

 nature, but long experience with such 

 seeds shows that oil is not a preserva- 

 tive property. For instance, such 

 large seeds as the Butternut, Hickory- 

 nut, Black Walnut and European Wal- 

 nut contain a large, fleshy, oily kernel ^Fiff. 41. 

 (figure 41), which, from appearances, ' 

 we might suppose would be able to resist ordinary adverse 

 conditions for a long time, but, on the contrary, they are 

 quite sensitive to extremes of any kind, and it is with 

 difficulty such nuts can be preserved alive and sound for 

 even a twelvemonth. If kept warm, a chemical change 

 takes place, and the oil in the kernel becomes rancid. In 

 a moist position the kernel soon decays, and, while a freez- 

 ing temperature will check decay, if it be long continued 

 the germ of the seed is destroyed. But, on the contrary, 

 the minute oily seeds of the Mustard will withstand con- 

 siderable drying, a high temperature or a low one, and 

 still retain their vitality for several years. Such minute 

 seeds as the common garden Pursley or Purslane (Por- 

 tulaca), will withstand great extremes of temperature, 

 also alternate soaking and drying while buried in the 

 soil, and yet survive these changes, while the great hard- 

 shelled nuts, as well as many of the seeds of our forest 

 trees, must grow, if at all, or die within a few weeks, or 

 months at farthest, after reaching maturity. There are, 



