20 SEEDLINGS. [SECTION 3. 



mainly, at the expense of the great store of food in the cotyledons. These, 

 after serving their purpose, decay and fall away. 



29. Such thick cotyledons never separate; indeed, they sometimes grow 

 together by some part of their contiguous faces ; so that the germination 



seems to proceed from a solid bulb-like mass. 

 This is the case in a horse-chestnut. 



30. Germinating Embryo supplied by its 

 own Store of Nourishment, i. e. the store in 

 the cotyledons. This is so in all the illustrations 

 thus far, essentially so even in the Flax. This 

 nourishment was supplied by the mother plant to 

 the ovule and seed, and thence taken into the 

 embryo during its growth. Such embryos, filling 

 f the whole seed, are comparatively large and strong, 



and vigorous in germination in proportion to the 

 amount of their growth while connected with the parent plant. 



31. Germinating Embryo supplied from a Deposit outside of It- 

 self. This is as common as the other mode ; and it occurs in all degrees. 



FIG. 36. Half of an acorn, cut lengthwise, filled by the very thick cotyledons, 

 the base of which encloses the minute caulicle. 37. Oak-seedling. 



Fio. 38. Half of a horse-chestnut, similarly cut ; the caulicle is curved down on 

 the side of one of the thick cotyledons. 39. Horse-chestnut in germination; foot- 

 stalks are formed to the cotyledons, pushing out in their lengthening the growing 

 parts. 



