98 



PRINCIPLES OF PLANT-TERATOLOGY. 



margin (PI. XXXVIII, fig. 6). Payer has shown that 

 in the development of the normal carpel two ovules 

 arise, of which one becomes abortive later; hence 

 teratological and developmental evidence combine to 

 show what the ancestral condition was like. 



In the same way, in a species of Zamia, three ovules 

 were seen instead of the normal two. 



Fig. 109. — Ophioylossum vuhjatum (Adder's- tongue Fern). Bifurcat- 

 ing "spikes" and tendency to increase in their number. (After 

 Freiberg.) 



(5) Sporophylls of Cryptogams. 



a. Sporophyll-segments. — In the adder's-tongue fern 

 [Ophioglossum vulgatum) and the moon wort (Botry- 

 chium) the sterile portion of the sporophyll may fork 

 more or less deeply; forking, to the second or third 

 degree, is the normal condition in 0. palmatum ; the 

 sterile is merely the terminal portion of the entire 

 sporophyll. It occasionally also happens in 0. vulgatum 



