Genetical Studies on Oenothera. V. 



187 



GiGLio-Tos rll) has found in the phenomenon confirmation of certain 

 of his laws of hybridization. Goldschmidt ('12) has suggested merogony 

 as an explanation and has published an account which claimed that the 

 female nucleus in the the embryo sac failed to fuse with the male and 

 finally disintegrated leaving the male nucleus alone to initiate and 

 carry forward the development of the embryo; a doubling of the 

 chromosome number in the descendants from the male nucleus was 

 assumed to take place at an early stage of embryo development. 

 Neither of these authors appears to have been sufficiently familiar 



ttunvs 



Vx 



f 



-tn X 



Fig. 16. Jlature buds. Biennis, sepal tips long and slender, bracts Vi — Va length of 

 the bud. Muricata, sepal tips shorter and thicker, bracts '/^ — 'g length of the bud. 

 Biennis < muricata, matroclinous in having sepal tips long and slender, and bracts 

 Yj — */, length of the bud. Muricata -^ biennis, matroclinous in having sepal tips shorter 

 and thicker, and bracts ^/j — Y* length of the bud. 



with the material to know that the patroclinous behavior does not 

 mean absolute identity of structure and that in these crosses there is 

 abundant evidence of hj-brid organization even though partially obs- 

 cured by their strong resemblance in certain characters to the pollen 

 parents. The statements of Goldschimidt have since been refuted by 

 his colleague Rexxer ('13) who reports normal fertilization in the hybrid 

 biennis X muricata and an embryo with the normal diploid number of 

 chromosomes. 



It would seem premature to discuss at this time hypotheses which 

 have been advanced by de Vries, or other views that may be suggest- 

 ed to explain the peculiaiities of these hybrids. We shall shortly, 



13* 



