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. Sueh 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 liorse-chestnut. 



30. Germinating Embryo supplied by its 

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

 tlie 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 

 the whole seed, are comparatively large and strong, 

 and vigorous in germination in proportion to the 

 amount of their growth while connected with tlie 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 aconi, cut lengthwise, filled by the verj' thick cotyledons, 

 the l)a.se of which encloses the minute caulicle. 37. Oak-seedlin|r. 



Fig. 38. Half of a horse-chestnut, similarlj' cut ; the caulicle is curved down on 

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

 stalks are formed to the cotyledous, j)ushing out in their lengthening the growing 

 parts. 



