CHAP, in 77/0 Morphology of the Floiver 89 



case of sporangia (Goebel, Bot. Zeit., 1881), and there is 

 just reason to be prepared for its being broken down also 

 as regards the parts which bear the sporangia ... it is, in 

 fact, suggested that the sporangiophores are simply pla- 

 cental growths, and not the result of any metamorphosis 

 of parts or appendages of prior existence.' 



The same idea was stated by Scott in his discussion of 

 the morphology of certain fossil forms, in the words, ' The 

 difficulty is perhaps met by regarding the sporangiophore 

 (like the sporangium itself), as an organ sui generis, which 

 often occupies the position of the ventral lobe of a bract, but 

 may also arise independently, and may so far resemble an 

 entire leaf.' 



Bower did not go so far as to suggest that the stamen 

 and carpel of the Phanerogams are modified sporangio- 

 phores. He concluded his general discussion of the mor- 

 phology of the latter by saying : ' But a warning is neces- 

 sary that mere form is not a sufficient characterization of 

 any given part as a non-foliar sporangiophore ; for in 

 some cases a clear line of evidence shows that certain parts 

 which have the form of stalk with vascular supply, enlarged 

 distal end, and pendent sporangia common for sporangio- 

 phores are truly of foliar nature ; I mean the female 

 sporophylls of the Cycads. The argument for reduction 

 from some more elaborate sporophyll is for them firmly 

 established on a comparative basis, and it seems hardly 

 open to doubt that they are foliar structures reduced from 

 some more elaborate Cycado-Filicinean leaves. But though 

 this may be true for the Cycads, it does not invalidate our 

 hypothesis for sporangiophores generally ; it merely 

 suggests that similar results, of which the biological advan- 

 tages are obvious, may be arrived at along different evolu- 

 tionary routes. It will also make caution especially neces- 

 sary in treating similar cases among seed plants.' 



The domination of the idea of metamorphosis led to 



