On the Further Development during Germination 
of Monocotylous Embryos; with _ special 
Reference to their Plumular Meristem. 
BY 
W. EDGAR EVANS, B.Sc., 
CARNEGIE FELLOW IN BOTANY. 
With Plates LIII-LIV. 
INTRODUCTION. 
THE germination of seeds, though by no means a neglected 
subject, is one which still requires much investigation. The 
chemistry and biology involved in the solution and absorption 
of perisperm and endosperm; the further development of 
the embryo both during and after germination, especially from 
the standpoint of phylogeny ; and the effects produced on this 
by differences in the environment of the seed at the time of 
_ germination—for example, deep as compared with shallow sowing, 
the results of chemical or physical stimulation, and the like,— 
these are a few of the lines of research which seem most likely ~ 
to repay fuller study. Moreover, it must not be thought that 
such problems need no more consideration because good work 
relating to them has been already published, for it will be found 
on examination that the gaps in our accurate knowledge often 
exceed the knowledge itself, making it even yet impossible to 
definitely or satisfactorily answer many an important question 
arising from the study of germination, 
Our information regarding the relation which leaf and stem 
bear to one another is an excellent example of this state of 
affairs, for there are at the present time two schools of botanists 
holding diametrically opposite views on the matter. Those 
of the first consider the leaf an essentially lateral structure ; 
. it has been evolved as a lateral outgrowth from the stem which 
bears it, while leaf-like organs which seem terminal in origin 
must be regarded in either of two ways—they are only apparently 
terminal, or they are not homologous with leaves. Botanists 
who uphold the second school maintain, on the other hand, that 
the leaf was originally terminal ; each successive leaf arose from 
{Notes R.B.G., Edin., No. XXI, August 1909. ] 
