LOBED COTYLEDONS 41 



The embryo is of the form shown in fig. 79 : the horn 

 or process r is the radicle ; the rest is the cotyledon, of 

 which the free end / is folded on itself and turned down- 

 wards. In this way the embryo fills the seed, leaving a 

 small space between the cotyledons and also between / and r 

 which is occupied by endosperm. Perhaps it may make the 

 arrangement clearer to take a piece of note-paper, cut it into 

 the form of an egg (fig. 80), turn the broad portion a b down- 

 wards, so that the parts a and 6 have their under faces turned 

 to one another, and then press down the line e f, and bring 

 the points c and d together, so that c ef and d e/have their 



FIG. 79. Embryo of Mallow. Enlarged. 



PIG. 81. 



FIGS. 80 and 81. Piece of paper prepared to show the mode and effect of the 

 folding of the embryo. 



upper surfaces together, and the apex / pointing downwards. 

 We shall then have an object shaped as in fig. 81, with a 

 sharp point at c, which would not conform to the rounded 

 shape of the seed. If, now, to make it do so, we cut off the 

 point c along the dotted line and then unfold the paper, we 

 shall find that it has the form of the cotyledon of Malva 

 (fig. 35) with a bay or notch on each side. In Erodium the 

 arrangement is somewhat similar, and it seems clear that the 

 lobes are due to the manner in which the embryo is folded. 



In (Enothera and some allied species the cotyledons also 

 present a terminal lobe. This, however, is not due to folding. 



