1909] LEAVITT—HOMOEOSIS IN PLANTS 



57 



while it is in itself not unlikely that the fertile scale represents a pair 

 of sporophylls belonging to an axillary shoot, and while comparative 

 morphology and anatomy may make this view even probable, the 



seems to me, add nothing material 



may 



1m 



To me 



from fertile scale to axillary 



appeal with the same compulsion with which they i 

 kovsky and some others. I can conceive the most 



transitions to represent combinations of historically unrelated form- 

 factors, reproductive on the one hand and vegetative on the other; 

 and in the conception I find nothing incongruous with other facts of 

 homoeosis. If there were originally no shoot in the axil of the fertile 

 leaf (the bract) but only an ovuliferous segment (Sachs-Eichler) or 

 pair of lobes (Delpino)— supposing for 

 were admissible on any but teratological evidence— and if by influx of 

 vegetative forces the cone were converted gradatim into an ordinary 

 branch , with buds in the axils of the leaves ; then it seems to me that 

 ^e might expect to discover morphogenetic impulses toward the 

 formation of ovuliferous segments and imDulses toward bud-formation 



argument 



same 



monstrous cones exhibit. After 



t> 



formative impulses 



fences generally, I do not feel that Celakovsky's case for the pre- 

 eminent value of anamorphoses is established. In comparison with 



minimal 



monstrous 



value. The interest and worth of Celakovsky's thorough- 

 going study of the whole subject does not lie in his treatment of 

 monstrosities. 



* et a smaU degree of approval for the theory which makes the 



from !? reSent a Sh ° 0t bearin S sporophylls might possibly be derived 

 ^1 frec l uenc y with which a shoot arises in the site of the scale; 



this 



appearand t t — ""&«c ^ g»»-" ^ ««< "^ uwu 



v dnce ot the shoot. The latter has been found in the genera 



r 1 ?' Plcea > Pinus, Tsuga, 



Cryptomeria 



Strohm C • *""5 i i-iypiuiii 



bUS ' Sec l U0l a, Taxodium, and some 



