ANTHOPHTTA. 



267 



Fig. 158.— Gfermination ot 

 Indian Corn. I, II, III, suc- 

 cessive stages. A and B, 

 front and side views of a 

 separated embryo ; w, root ; 

 e, part of seed filled with en- 

 dosperm ; sc, cotyledon ; r, 

 its open margins ; b, h', h*', 

 leaves of young plant; I, 

 fragment of wall of ovary. 

 Natural size. 



endosperm; anteriorly it is curved 

 entirely around the remainder of 

 the embryo. 



505. Under proper conditions the 

 main root pushes through the root- 

 sheath (tvs, Pigs. 157, 158). The 

 plumule, consisting of a minute stem 

 and a few rudimentary leaves, next 

 pushes out through the upper end of 

 the curved cotyledon (//, Fig. 158). 

 The cotyledon remains in contact 

 with the endosperm and absorbs 

 nourishment from it for the suste- 

 nance of the growing parts. Lateral 

 roots soon appear upon the main 

 root, and adventitious ones arise 

 from the first internodes of the stem 

 (w'", w". w'). The first leaf above 

 the cotyledon is quite small {b), and 

 each succeeding one becomes larger 

 and larger until the full size is 

 reached. 



506. The primitive flower of the 

 Monocotyledons is well illustrated 

 by the Water- plantains, in which the 

 parts are all free from one another. 

 The Lilies show a higher structure 

 in their compound ovary, while in 

 the Irises the inferior ovary marks 

 a still greater advance, which cul- 

 minates in the Orchids, the highest 

 members of the sub-class. The 



