20 



SEEDLINGS, 



[section 3. 



inaiuly, at the expense of the great store of food iu the cotyledons. These, 

 after serving their purpose, decay and fall awaj. 



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

 together by some part of tlicir 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 

 tlie cotyledons. This is so iu all the illustrations 

 thus far, essentially so even in the Tlax. 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 tlieir growth while connected witli the parent plant. 



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

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



Fxo. 36. Half of an aconi, cut Iengthwi.se, filled by the very thick cotyledou.s, 

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



Fig. 38. Half of a hoise-ctie.stnut, 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. 



