with Hieraciiim 101 



partially fertile ; H. Auricula $ x H. Pilosella $ as slightly 

 fertile, and H. Auricula $ *H. aurantiacum $ as unfertile. 

 Of the two forms of the last named hybrid, the red-flowered 

 one was completely sterile, but from the yellow-flowered 

 one a single well-formed seed was obtained. Moreover it 

 must not pass unmentioned that among the seedlings of the 

 partially fertile hybrid H. prccaltum ? x H. aurantiacum <$ 

 there was one plant which possessed full fertility. 



[3.] As yet the offspring produced by self-fertilisation 

 of the hybrids have not varied, but agree in their characters 

 both with each other and with the hybrid plant from which 

 they were derived. 



From H. prcealtum $ x H. flagellare $ two generations 

 have flowered ; from H. echioides ? x H. aurantiacum $ , 

 H. praialtum ? x H. aurantiacum & , H. Auricula ? x H. 

 Pilosella $ one generation in each case has flowered. 



4. The fact must be declared that in the case of the 

 fully fertile hybrid H. echioides $ x H. aurantiacum $ the 

 pollen of the parent types was not able to prevent self- 

 fertilisation, though it was applied in great quantity to the 

 stigmas protruding through the anther- tubes when the 

 flowers opened. 



From two flower-heads treated in this way seedlings 

 were produced resembling this hybrid plant. A very 

 similar experiment, carried out this summer with the 

 partially fertile H. prcealtum ? x H. aurantiacum < led to 

 the conclusion that those flower-heads in which pollen 

 of the parent type or of some other species had been 

 applied to the stigmas, developed a notably larger number 

 of seeds than those which had been left to self-fertilisation 

 alone. The explanation of this result must only be sought 

 in the circumstance that as a large part of the pollen-grains 



