338 
Holden. — Observations on the 
the arrangement of the leaves diverges very widely from the normal, so 
much indeed that it is impossible to correlate it at all closely with that of 
the remaining seedlings studied. Whether this divergence is an extreme 
expression of the .effect of compression it is impossible, on such limited 
evidence, to say, but leaf A and, judging from the behaviour of its vascular 
strands, leaf A i in both seedlings arise at the first epicotyledonary node, and 
leaves B and B i at the second epicotyledonary node. Beyond these it is 
difficult to assign values, and little useful purpose would be served by 
the attempt. 
Figs. 101-106. Epicotyls of two Group II seedlings showing considerable modi- 
fication of the leaf arrangements. Figs. 101-105 are from one seedling and Fig. 106 
from a second. 
Three views seem to be possible as to the origin of this group, and 
these may be briefly stated as follows : 
(i) That the monocotylous condition is due to the suppression of one of 
the cotyledons, that is, the condition is heterocotylous in origin. 
(ii) That the monocotylous condition is due to a degree of syncotyly of 
so extreme a character that there is no anatomical evidence of the double 
origin of the resultant cotyledon remaining. 
(iii) That one of the cotyledons has retained its normal characteristics, 
whilst the other has become entirely leaf-like and is represented by the 
first epicotyledonary leaf. 
The points in favour of the first hypothesis are based chiefly on the 
character of the cotyledon. The simplest member of the series exhibits 
