490 SLossoN: THE ORIGIN OF 
against whole prothalli of C. rhizophyllus. In a fifth pot a few 
whole prothalli of both ferns were planted against each other. In 
all about fifty pairs of prothalli were planted. 
Now, if in the third pot antherozoids were set free on one of 
the whole prothalli of A. platyneuron and some were to fertilize the 
archegonia on the archegonial section of C. rhizophyllus in contact 
with that prothallus, in all probability some also would fertilize the 
archegonia on the whole prothallus. Hence, should a hybrid- 
plant develop, we would expect a plant of pure A. platyneuron to 
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develop at the same time. That is what occurred. In June # 
plant, unquestionably a hybrid between A. platyneuron and ‘ ; 
rhizophyllus, and a plant of pure A. platyneuron sprang UP ae 
