ORIGINAL RESEARCH. 



(I) Parthenogenesis in Nicotiana. 



By ROSE HAIG THOMAS. 



I NOTICED last year and this summer that in several 

 different cross fertilisations, made between different 

 species of Nicotiana, some plants bearing only the 

 characters of the ovule parent were produced along 

 with others which were apparently Fi hybrids. Upon 

 the first and second occasion when I obtained these 

 results — which occurred with reciprocal crosses of 

 Nic. Sylvestris x Nic AJfinis. — I thought they must 

 be due to accident, for muslin bags had been used, 

 and it was possible that pollen from adjacent flowers 

 of the same plant may have gained access through 

 the bag. I repeated the experiment a third and a 

 fourth time, with every precaution, such as the use 

 of wax-paper bags and the cleansing of the pollinating 

 instruments in spirit before use. At both repeti- 

 tions of the experiments the same phenomenon 

 was manifested. I then began to suspect the 



cause, and determined to test Nicotiana for 

 parthenogenesis . 



In the first few trials the method employed was 

 to cut off the anthers alone, but later, after success 

 attended these I cut off both stigma and 



