PROLIFERATION. 



25 



Baillon regarded the scale as of axial nature from 

 the fact that during the early development of the cone 

 it arises as a simple papilla in the axil of the " bract," 

 not recognizing the fact that structures may be con- 

 genially modified, the early stages through which the 

 present structure has passed in the phylogenetic history 

 not being represented in the ontogenetic development. 

 Schleiden, also relying on the mode of development, 

 held the scale to be an axial placenta. 



Strasburger also held that the ovuliferous scale was 

 of the nature of an axillary shoot ; he regarded it as a 

 kind of flattened axis or disk, chiefly on account of its 

 late development compared with that of the ovules ; 

 the abnormal structures above cited he regarded as the 

 result of the struggle waged between two opposing 

 forces, viz., the vegetative development of the cone and 

 the normal formation of reproductive organs, in which 

 the former had for the time being overbalanced the 

 latter. This position, however, Celakovsky shows to 

 be perfectly untenable ; for it is impossible for an organ 

 belonging to one morphological categorj^, such as an 

 axis or disk, to become transformed into those belonging 

 to another category, such as the foliar appendages of 

 an axis. 



Masters maintained that the ovuliferous scale is a 

 half-cladode, i. e. an axial enation from either the bract 

 or the axis of which the lower or outer portion has 

 become abortive (cf. C. de Candolle's ' Theorie de la 

 Feuille'). This view cannot be said to have found 

 any support. 



Just as Schleiden and Baillon followed the develop- 

 mental method, and Celakovsky and others the terato- 

 logical and comparative, so Van Tieghem followed the 

 anatomical method in the endeavour to solve this 

 problem. His idea is that the seminiferous scale in 

 all Coniferse represents the first and only leaf of an 

 axillary branch, though he suggests the possibility of 

 its being really two fused leaves. His view is based 

 on the course and orientation of the vascular bundles 



