334 
cular system, because they considered the stele as a structure 
sui generis. In some recent work (Thompson (57), Cribbs 
(12)), the attention of the investigator is diverted chiefly to the 
theory of recapitalution. Thompson (37) finds that the ,,çsum 
of available ontogenetic evidence is small.” Jeffrey (20) re- 
marks that ,,the sceletal structure of vascular plants has in the 
past been used for phylogenetic purposes to a much smaller 
extent than that of the higher animals.” Probably this 1s one 
of the chief causes for the monopoly of the stelar theory at the 
present time. The embryological evidence is mainly 
in favor of the phytonic view. It is because of the 
phytonic facts observed in the embryo of Lycopodium cernuum 
by Treub (38) and in Phylloglossum drummondi that Bower (3) 
writes ; that ,,early embryological detail is an insecure guide 
for purposes of comparison.” 
This statement will become clear to us when we keep in mind 
that the theory of the strobilus, as advocated by Bower may be 
considered as embodying the morphological expression of the 
stelar axioms. 
It is remarkable that in the great number of investigations 
carried out in this connection — from the time of Leclerc du 
Sablon (23) up to the recent work of Cribbs (12), there are 
very scanty data either supporting or opposing the stelar axiom. 
This is, in our opinion, due to the employment of inadequate 
methods already used by van Tieghem in the description of 
the stele. Van Tieghem speaks about parts of the stele which 
8e rompent or ,,se reploient . Recent authors speak about 
the leaf trace departs” or ,,the leaf trace joins” according to 
the sequence in which they examined their slides. Consciously 
or unconsciously they look at these terms as expressing the 
real course of the ontogeny. A structure is described always 
from top to bottom or from bottom to top; the real trend of 
development being in many directions. 
The results of Campbell (9) on the development of Eu- 
sporangiate ferns seem to indicate, however, that other con- 
