ANTHOPHTTA. 275 



the endosperm having all heen absorbed. The thick coty- 

 ledons lie face to face, and are attached below to the small 

 stem of the embryo-plant. The stem extends upward a 

 short distance between the cotyledons, bearing a few rudi- 

 mentary leaves and itself ending in a growing point, the 

 whole constituting the plumule. The downward prolonga- 

 tion of the stem (commonly, but erroneously, called the 

 radicle, for it is not a little root) ends in a very short root 

 which is continuous with the stem. 



521. Under the proper conditions of heat and moisture 

 the root elongates and pushes out through the pore (micro- 

 pyle) of the seed-coat; at the same time the stalks of the 

 cotyledons elongate and thus bring the plumule outside of 

 the seed-coat, the cotyledons alone remaining within. 

 During the first few days of its growth the young plant is 

 nourished by the starch in the cotyledons, which in this 

 species remain during the whole process of germination 

 beneath the ground enclosed in^the seed-coat. In the com- 

 mon Pield-bean (Phaseolus) the germination is the same 

 excepting that the stem elongates below the cotyledons 

 and brings the latter above the ground. 



522. The seed of the Castor-oil Plant contains a large 

 embryo surrounded by a thin layer of endosperm (Fig 

 163. 7). In its germination the root and stem below the 

 cotyledons elongate, and thus bring the seed-coat with the 

 contained cotyledons above the ground (Fig. 163, 77). 

 The cotyledons remain within the seed-coat until they have 

 absorbed all of the endosperm ; when this is accomplished, 

 the empty seed-coat falls away, and the freed cotyledons 

 expand and assume to some extent the functions of ordi- 

 nary foliage-leaves. 



523. The venation of the leaves of Dicotyledons is easily 



