An Anatomical Study of Syncotyly and Schizocotyly. 
BY 
R. H. COMPTON. 
With forty-one Figures in the Text. 
Introduction. 
O NE of the most momentous events in the history of Systematic Botany 
and Phylogeny was the perception by Andrea Cesalpini (1583) of 
the fundamental importance of characters of seed and embryo in plant 
classification. John Ray's division of the Flowering Plants into Dicotyle- 
dons and Monocotyledons (1686-1704) has been the basis of the systematic 
study of Angiosperms ever since. The success of this primary division is 
perhaps due to the fact that characters which appear early in ontogeny are 
on the whole more likely to indicate remote ancestral affinities than those 
which develop later. The same cause has led to the modern reawakening 
of interest in seedling structure. In the vexed question of the origin of the 
Monocotyledons seedling characters have been the main point upon which 
attention has been focused. 
The admirable simplicity of the classification of Angiosperms according 
as they have one cotyledon or two could not in the nature of things but be 
disturbed at some point. It was found that certain undoubted Dicotyledons 
had no seed-leaves recognizable as such ; others had only one cotyledon ; 
and others again had several ; while in the Monocotyledons the question 
was often — and still is — what form has been taken by the cotyledon which 
we assume to be present. Moreover, teratologists found that material was 
provided them by seedlings just as by all other plant structures. Some- 
times a seedling of a Dicotyledonous species was found to have but a single 
seed-leaf ; sometimes it had three or four, or the cotyledons were lobed to a 
greater or less depth. 
It is with this last class of variation that I propose to deal in the 
following paper. The study of teratology is full of intrinsic interest and is 
often of great value in elucidating obscure morphological problems. The 
question as to the modes of increase and decrease in number of cotyledons 
is of such great phylogenetic importance that one is impelled to investigate 
[Annals of Botany, Vol. XXVII. No. CVIII. October, 1913 ] 
