8o Sargant.— Theory of the Origin of Monocotyledons 
adaptation to this habit. When we consider the conditions 
under which a typical geophyte lives, it is very clear that its 
seedlings must be even more perfectly adapted to the environ- 
ment than the mature plant in order to have a chance of 
surviving. 
The seed formed at the end of the growing period is 
commonly capable of resisting a considerable degree of cold 
or drought in the long dead season. When the genial weather 
returns and it germinates, the seed is confronted with a 
difficult problem. During the short period of vegetation the 
growth of the seedling must proceed in such a way that the 
structure completed by the end of the season is capable of 
living through the severe weather which follows. 
Accordingly we find that the seedling begins at once to 
form its underground organs. Not unfrequently the whole 
structure remains underground during the first season of 
growth (Megarrhiza Californica, Darwin, 10 , p. 82 ; Arum 
maculatum, Rimbach, 33 ). More commonly the cotyledons 
only appear above ground in the first season (E rant his 
hiemalis , Fritillaria imperialis), or the cotyledons may remain 
underground in the seed and the first leaf break through the 
soil {Anemone nemorosa, Irmisch, 23 , p. 17, Figs. 26-28 ; Eucomis 
nana, Jacq.). In other species both cotyledons and foliage 
leaves come up above ground in the first season and act as 
assimilating organs {Delphinium nudicaule, Iris sp.). 
In all these cases, however, the production of assimilating 
surfaces seems to be an object of secondary importance to the 
seedling of a geophilous plant in its first season. The forma- 
tion of adequate subterranean organs at a safe distance below 
the surface of the soil is the condition on which the life of 
such a seedling ultimately depends, and its powers are devoted 
in the first place to this task. 
Concrescent cotyledons seem to be an adaptation for pro- 
ducing effective assimilating surfaces with the least possible 
expenditure of material (Lubbock, Sterckx, 1 . c.). The pro- 
duction of a single cotyledon, whether by the more complete 
fusion of two or in any other way, is also an economy as 
