VOLUME XLIV 



NUMBER I 



Botanical Gazette 



\ 



JULY igo-j 



HYBRIDIZATION AND GERM CELLS OF OENOTHERA 



MUTANTS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 



XCIII 



Reginald Ruggles Gates 



my 



as 



of the stages in pollen development in the O. Lamarckiana hybrid 

 obtained by crossing O. lata with O. Lamarckiana pollen, further 

 investigations have placed in a new light the situation in regard to the 

 number of chromosomes in the Oenothera mutants and hybrids 

 studied. The further facts obtained have disclosed quite a different 

 condition from the one anticipated, and one which is at present wholly 

 inexplicable, and apparently quite unique so far as chromosomes arc 

 concerned, though it is to be expected that fuller knowledge of the 

 facts will bring an explanation of the situation. Since the facts, so 

 far as known at present, appear to be most directly concerned with 

 Oenothera hybrids, a brief account of the forms of hybridization 

 among the Oenothera mutants, as developed by the very extensive 

 hybridizing experiments of DeVries/ will first be necessary. 



FORMS OF OENOTHERA HYBRIDS 



In general, DeVries' experiments appear to disclose at least three 

 main forms or types of hybridization in the Oenothera mutants: 

 (i) hybrids between a mutant and the parent O. Lamarckiana; 



» Gates, R. R., PoUen development in hybrids of Oenothera lata X O. Lamarck- 

 iana, and its relation to mutation. Box. Gazette 43:81-115. pis, 2-4. 1907. 



2 DeVries, Hugo, Die Muutionstheorie, Vol. 11. 1903. 



