654 A TEXTBOOK OF THEORETICAL BOTANY 



it in the form of a sheath. This was the view of Hofmeister (1863). 

 It differs from that of Potonie only in its implications, for it accepts 

 the stem and leaf as distinct morphological categories and does 

 not envisage the origin of the central primitive axis by overtopping 

 from a dichotomous thallus. 



The Leaf-skin theory of Saunders (1922) is essentially similar to that of 

 Hofmeister. It is based on anatomical characters and does not concern itself 

 with evolutionary ideas. 



One must recognize that much of the diversity of opinion revealed by the 



D E F 



Fig. 658. — Diagram to illustrate various theories of the relationship 

 between leaf and axis in Spermatophyta. Leaf segments stippled, 

 axis segments white. The basal cone represents the primary root. 

 A, The classical view. Leaf and axis as independent categories ; the 

 basis of the strobilar theory. B, The original phytonic view, each 

 leaf growing from a distinct segment of the axis (Celakovsky and 

 Gaudichaud). C, The axis entirely composed of decurrent leaf 

 segments (Delpino). D, The shoot composed of a bundle of axial 

 segments, the terminations of which become leafy. The telome view. 

 E, The shoot contains an axial core surrounded by a sheath of 

 decurrent leaf bases (Hofmeister). F, The shoot contains an axial 

 core surrounded by a " pericaulome " of the bases of lateral branch 

 segments. 



above analysis (Fig. 658) rests upon the acceptance of a too rigid categorization 

 of organs, and the belief, for instance, that a leaf continues to be somehow, 

 mystically, a leaf even when it appears to be part of a stem. Once let us 



