200 ANATOMICAL EVIDENCE 
It appears, then, that the anatomical evidence is consistent with the 
early existence of a small-leaved type of shoot in Vascular Plants. Com- 
parative anatomists are practically unanimous in recognising the non- 
medullated monostele as the primitive stelar type, from which the more 
diffuse vascular types with medulla, and ultimately with separate strands, 
or it may be a dictyostelic state, were derived. Translated into terms of 
general morphology, this opinion indicates a primitive state where the axis 
was structurally dominant in the shoot. The derivation of more complex 
anatomical arrangements from the non-medullated monostele suggests an 
Fic, ror. 
Embryo of Lycopodium cernuum, after Treub, s=suspensor. J=foot. v=root. 
cot=cotyledon. "The numerous protophylls contain each a vascular strand, which is 
however disconnected from the rest. 
increasing influence of the leaf in the shoot at large, which finds its anatomical 
expression in various types of resolution of the stele into separate strands. 
The general conclusions from anatomy thus appear favourable to a strobiloid 
theory of the shoot, and lead us to contemplate a primitive condition, in 
which the axis was the dominant factor and the appendages of subordinate 
importance. And as this coincides with the story of individual develop- 
ment of the leaf upon the axis in all normal shoots, that coincidence should 
go far in supporting a strobiloid theory of the shoot in the sporophyte 
generation. 
