12 Weiss, Researches on Heredity hi Plants. 



Exact statistical experiments regarding the inheritance 

 of immunity and susceptibility to disease in plants are 

 however peculiarly difficult to conduct, and have only been 

 undertaken by ver}- few investigators, so that we shall have 

 to remain content for the present with the general conclu- 

 sion that these peculiarities, whether of the nature of unit 

 characters or combinations of such, behave in a general 

 way like other distinctive characters of living organisms. 



That these and similar investigations on plants and 

 animals are of far-reaching importance, who can doubt? 

 A general understanding, indeed, of the laws of inheritance, 

 which seem to be so remarkably uniform in the vegetable 

 and animal kingdoms, is not only essential for the advance 

 of the biological sciences, but is a basis for the economic 

 and social progress of mankind. 



EXPLANATION OF PLATE. 



Fig. I. Seedling of tlie Greater Celandine {C/ielidonimn viajus). 



-Fig. 2. Seedling of the cut-leaved variety of the Celandine 

 {C/ielidonim?! ma jus var. laciniatum). 



Fig. 3. Flower of the Water Avens {Geuin rivale). 



Fig. 4. Flowers of Geum intermedium, the hybrid between the 

 Water Avens and the Common Avens. Note the 

 intermediate curving of the flower stalk. 



Fig. 5. The Common Avens {Geum urbanum), with small erect 

 flowers. 



Fig. 6. One of the descendants in the second filial (/2) genera- 

 tion of Geum intermedium, with white petals. The 

 flower had the droopmg habit of Geum rivale, but 

 shorter petals. 



