102 Mendel's Experiments 



of the hybrid, examined microscopically, show a defective 

 structure, a number of egg-cells capable of fertilisation do 

 not become fertilised by their own pollen in the ordinary 

 course of self-fertilisation. 



It not rarely happens that in fully fertile species in the 

 wild state the formation of the pollen fails, and in many 

 anthers not a single good grain is developed. If in these 

 cases seeds are nevertheless formed, such fertilisation must 

 have been effected by foreign pollen. In this way hybrids 

 may easily arise by reason of the fact that many forms 

 of insects, notably the industrial Hymenoptera, visit the 

 flowers of Hieracia with great zeal and are responsible for 

 the pollen which easily sticks to their hairy bodies reaching 

 the stigmas of neighbouring plants. 



From the few facts that I am able to contribute it 

 will be evident the work scarcely extends beyond its first 

 inception. I must express some scruple in describing in 

 this place an account of experiments just begun. But the 

 conviction that the prosecution of the proposed experiments 

 will demand a whole series of years, and the uncertainty 

 whether it will be granted to me to bring the same to a 

 conclusion have determined me to make the present 

 communication. By the kindness of Dr Nageli, the 

 Munich Director, who was good enough to send me species 

 which were wanting, especially from the Alps, I am in a 

 position to include a larger number of forms in my 

 experiments. I venture to hope even next year to be able 

 to contribute something more by way of extension and con- 

 firmation of the present account. 



If finally we compare the described result, still very 

 uncertain, with those obtained by crosses made between 

 forms of Pisum, which I had the honour of communi- 

 cating in the year 1865, we find a very real distinction. 



