26 



PRINCIPLES OF PLANT-TERATOLOGY. 



from the axis into the scale. It is doubtless very useful 

 to have these anatomical data furnished for us, but to 

 rely upon them as the sole criterion for explaining the 

 phenomenon in question is decidedly unsafe, to say 

 the least of it, e. g. we know that in all Coniferse an 

 axillary shoot always bears a pair of opposite leaves 

 and not a single leaf. 



Then there is the view of Sachs and Bichler that the 

 ovuliferous scale is a ventral outgrowth from the open 

 carpel (the "bract") of the nature of a placenta or 

 ligule; in the Cupressinese, TaxodineaB, Podocarpese, 

 and Agat/i .is no differentiated ventral outgrowth exists, 

 but the scale as a whole represents a carpel. 



Eichler's explanation of the abnormalities was this : 

 that the pressure exercised by the axillary bud arising 

 between the seminiferous scale and the axis of the cone 

 was the agency responsible for the splitting of the scale 

 into two parts and the wide separation of these into 

 the positions which they occupy, one on either side of 

 the axillary bud. But Celakovsky says that this theory 

 will not hold good when it is found that the splitting 

 of the scale frequently occurs when the axillary bud is 

 suppressed or exceedingly reduced, and also when it 

 arises on the anterior side of the seminiferous scale ; 

 a fact which is fatal to Eichler's placental or emer- 

 gence-theory, which is, however, best refuted by the 

 continuous, gradual transitions which occur in the ab- 

 normalities between the seminiferous scale and the first 

 leaf-pair, plus the anterior leaf, of the axillary bud. 

 And further, if this view of Eichler's be correct, what 

 has become, he asks, of the first transverse leaf-pair 

 of the bud, which should occupy the position taken up 

 by the separated parts of the seminiferous scale ? 



Delpino and Penzig put forward a theory which is 

 strikingly ingenious and original. According to them 

 the ovuliferous scale represents two basal lateral lobes 

 of the carpel (" bract ") which have become folded over 

 on to the upper face of the carpel and united by their 

 margins to form a single leaf-like organ bearing the 



