VOLUME XLV 



NUMBER 5 



Botanical 



Gazette 



MA Y 1 90S 



APOGA^IY IN NEPHRODIUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 109 



Shigeo Yamanouchi 



(with plates IX AND X, AND THREE TEXT FIGURES) 



Introduction 



The term apogamy was proposed by De Bary in 1878, following 

 Farlow's discovery (21, 22) that in Pteris crctica, under artificial 

 culture, the sporophyte is developed from the gametophyte with the 

 suppression of the sexual act. Since this discovery, the apogamous 

 development of a sporophyte as a vegetative outgrowth from the 

 gametophyte in pteridophytes, together with the phenomena of par- 

 thenogenesis, where the sporophyte is developed from ah unfertiUzcd 

 egg, has been described in many forms. 



Farlow (22), in contrasting the apogamous embr}-o with the 

 normal one, notes the following four points: (i) the apogamous 

 embryo is intimately connected with the prothallium in such a way 

 that one cannot decide where the one begins and the other ends; 

 (2) there is formed no foot or equivalent organ; (3) the vascular 

 bundle of the sporophvte is in direct connection with vessels^ which Ue 

 wholly in the prothallium; (4) the order of evolution is different a 

 leaf arising first and becoming tolerably well developed before the 

 root and afterward the stem make their appearance. 



Farlow's investigation was followed by an extensive study of 

 De Bary (i) on a number of forms in Polypodiaceae, in which he 

 described a similar 



sporophytic growth in Aspidi 



falcatum 



He records various conditions of the 



sexual organs in apogamous prothalUa: inAsp 



289 



