VOLUME XLV NUMBER 5 



LIBRARY 



NBW YORK 

 BOTANICAL 



iAKUtoK 



Botanical Gazette 



MA Y 1 90S 

 APOGAMY IN NEPHRODIUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY IO9 



Shigeo Ya manouchi 

 (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 cretica, 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 an unfertilized 

 egg, has been described in many forms. 



Farlow (22), in contrasting the apogamous embryo with the 

 normal one, notes the following four points: (1) 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 sporophyte is in direct connection with vessels which lie 

 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 Aspidium Filix-mas 



^ cristatum and A. jalcatum. He records various conditions of the 



development of sexual organs in apogamous prothallia: in Aspidium 



CO 



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