LKSSON 3.] GROWTH OF THE PLANT FROM THIi SKKD. 



17 



P<If, ;in(l >lioiil(l do ^o, liy examining pniiiis of Indian Corn, ."oakcd 

 in water, before and alj^o during germination. In tiic Onion, Lily, 

 and till'. Iris (Fig. 4o), the nionocotyledonons cndjryo is siinplcr, 

 consisting apparently of n simple oblong or oylindrieal 

 body, in wliicli no distinction of parts is visible : the lower 

 end is radicle, and from it grows the root ; the rest is a 

 cottjledon, which has wrapjx'd np in it a niinute piiinntle, 

 or bud, that shows its<'lf when the seeds sprout in germi- 

 nation. The first leaf which ap|)ears above ground in all 

 these cases is not the cotyle<lon. In all seeds with one coty- 

 ledon to the embryo, this remains in the seed, or at least 

 its upper part, wliile its lengthening base comes out, so as 

 to extricate the ])lumule, which shoots upward, and de- L 

 velops the first leaves of the plantlet. These appear one 

 above or within the other in succes- 

 sion, — as is shown in Fig. 42 and 

 Fig. 44, — the first commonly in the 

 form of a little scale or imperfect 

 leaf; the second or third and the *' 



following ones as the real, ordinary leaves of 

 the plant. Meanwhile, from the root end of 

 the embryo, a root (Fig. 41, 44), or soon a 

 whole cluster of roots (Fig. 42)^ makes its 

 appearanc<\ 



33. In Pines, and the like, the embryo con- 

 sists of a radicle or stemlet, bearing on itr. 

 summit three or four, or often from five to 

 ten slender cotyledons, arranged in a 

 circle (Fig. 45), and expanding at 

 ^1(0^ once into a circle of as many green 

 leaves in germination (Fig. 4(1). Such 

 embryos are said to he poh/rotijledonoiis, 

 that is, as the word denotes, many- 

 y cotyledoned. 



34. Plan of Vriflntion. The student 



who has underslandingly followed the 

 growth of the embryo in the seed into the seedling plantlet. — com- 

 jM)se(l of a root, and a st<in of two or three joints, each bearing a 



FIC. 41. (irnin of Indian (^irn in prrnilnati-jn. 

 FK;. -V-L 'I'Iio aanio, further advanrod 



2* 



