FERN GROWING 71 



will be the Influence of three germs, with the same pecu- 

 liarities, combining with three different sperms, each having 

 its own character. 



Turning to the experiment of an equal arnount of spores 

 of two varieties, when sown together, giving the characters 

 of both in all the progeny, instead of a portion only having 

 the character of one variety, allusion is here made to the 

 experiment with a normal and a crested variety, where in a 

 thousand seedlings only three were normal, or in proportion 

 of 333 to I. Were a single sperm only to act on a single 

 germ, we should naturally expect two hundred and fifty plants 

 like the normal variety, and two hundred and fifty like the 

 crested one. Two hundred and fifty would be the crested 

 crossed with the normal, and two hundred and fifty the normal 

 form crossed with the crested ; this would give seven hundred 

 and fifty with crests, and two hundred and fifty without, which , 

 is a strikingly different proportion, being as three to one. 



If this impregnation were extended to more cells, and 

 assimilation admitted, it would be possible to account for even 

 greater variations ; but this does not explain the result if two 

 varieties alone are sown together. No one can deny the 

 fact that the peculiarities of three or more varieties have 

 been produced by one and the same impregnation (the plants 

 unmistakably show this) ; but as to whether this has resulted 

 from the action of more than one sperm on one germ, or of 

 more than one germ on a prothallus, being each fertilised 

 by a single sperm, or a number of sperms acting on several 

 germs on the same prothallus, assimilating and imparting all 

 their peculiarities to one of these germs, the conclusion arrived 

 at must in any case be in opposition to the assertion that 

 only one sperm can act on a germ. And this seems to hold 

 good as regards the pollen of flowers, as is shown by a 

 repetition of the experiments on single dahlias. In crossing 

 a white with a red dahlia very few of the seedlings were 



