93 



asexual plant of similar morphological relations. 



The proof of this hypothesis must rest on actual cul- 

 tiu'al experiments, and it is much to he desired that such 

 experiments he ca,rried out. 



Since STEASBlIRCrKR ('94) showed that in the Archegoni- 

 ates the douole niuiiber of claro:nosomes is characteristic of 

 the sporophyte and tlie single nujaber of the gametophyte, 

 the main facts have oeen confirmed in so many forms tha.t 

 many "botanists ha.ve come to consider that the cliromosome 

 number alone is a trustworthy guide for the identification 

 of the two generations: that plants showing the diploid 

 condition of the nucleus necessarily belong to the sporo- 

 phi'-te, and that where tlie haploid condition of the nucleus 

 obtains, the gametophyte is necessai-ilj'' involved. Bota- 

 nists have come to speak of the sporophyte as the "2x-gen- 

 oration" ^LOTSY, *04) , and of the gametophyte as the "x- 

 generation"; and undoubtedly within tlie Archegoniate series 

 such a conception is very useful. However, even in Arclie- 

 goniates, where the rule is so generally applicable, recent 

 v/ork tends to shovT that the diploid condition of the nu- 

 cleus is not necessary for the differentiation of the sporo- 

 phyte ( YAI-IAirOTJCHI , *07), nor is the I'laploid condition nec- 

 essary for the differentiation of the gajnetophyte (JAKuITIR 



