MONOCOTYLEDON ES. 



451 



cate their real affinities. Unfortunately for us, however, 

 none of our systematic manuals follow any of the Continen- 

 tal systems ; we are compelled, therefore, to use for the pres- 

 ent the prevailing form of the Candollean system. In this 

 book the sequence of the groups is the reverse of that in 

 most American and English books, in order to bring the ar- 

 rangement of Angiosperms into harmony with that of the 

 rest of the vegetable kingdom. 



Sub-Class I. Mon-ocotyledostes. 



[Endogenm of De Candolle.*) 



550. — in these plants the first leaves of the embryo are 



alternate, hence we say 



that they have one cotyle- 

 don. The venation of the 

 leaves is for the most part 

 such that the veins run 

 more or less parallel to 

 one another, and when 

 they anastomose enclose 

 four-sided areolse ; rarely, 

 however, their veins are 

 irregularly distributed, 

 and they anastomose so as 

 to form an irregular net- 

 work. 



The germination of Monoco- 

 tyledons may be illustrated by 

 a couple of examples. In tLe 

 seed of the Indian corn the 

 embryo lies partly imbedded 

 in one side of the large endo- 

 sperm (Fig. 331). The first leaf 

 of the young plant (the cotyle- 

 don or scutelluni, Pig. 331, «c ) 

 with the endosperm ; anteriorly 



Fig. 3.31. — LongitufJiTial Bection of the Beed 

 of Indian corn (Zea Mais), c, adherent wall 

 of tlie ovary ; n, remains of the style ;/«, 

 l)ase of the ovary ; all the remainder of tlie 

 figure is the true seed ; eg, ew, endosperm ; 

 8^ — ss, cotyledon of embryo ; e, its epider- 

 mis ; A, plumule ; w (below), the main root ; 

 MS, the root-sheath; w (above), adventitious 

 roots springingfrttm the first iuternodeof the 

 stem. X C— After Sachs. 



has ita broad dorsal surface in contact 



* From the Greek Ivchv, within, and yifciv, to bring forth; Tlie 

 name was given under the fal^e impression that thepe plants were 

 " inpide growers," and the Dicotyledons " outside growers," 



