Varietäten, Descendenz, Hybriden. 259 



p. 203—207. 1917.); according to East the main theses defended in 

 Moore's paper are both based upon incorrect observations and 

 upon fallacious reasoning. The paper contains some interesting 

 experiments to test the effect of cross-pollen tubes on self-pollen 

 tubes. These experiments indicate clearly, that if pistils were polli- 

 nated with a number of cross-pollen grains and of self-pollen grains, 

 no self-pollen tubes contributed toward the production of the seeds; 

 only crossbred plants resulted. M. J. Sirks (Wageningen). 



Hagedoorn, A. L. et A. C. Hagedoorn-la Brand. Partheno- 

 genese bij hoogere planten. (Teysmannia XXVII. p. 643—656. 

 1 pl. 1916.) 



Les recherches de Mme Haigh Thomas (qui avait obtenu 

 des fruits renfermant de graines ä pouvoir germinatif par des fleurs 

 non pollinisees de concombres) ont porte M. et Mme Hagedoorn 

 ä examiner si cette graine serait nee par apogamie (c. ä. d. des 

 gametes ä nombre somatique de chromosomes). Les auteurs ont 

 choisi pour objet d'experiences les courges; puis ils firent artificiei- 

 lement les croisements suivants: Türkenbund X Poire bicolore; 

 Türkenbund X Yellow Bush Squash; Türkenbund X Courge-melon ; 

 Cococelle X Courgeron de Geneve et Vegetable Marrow X Miracle. 

 De ces plantes F x les fleurs feminines furent fermees ä fil de plomb 

 avant leur eclosion, tandisque les auteurs oterent autant que possibles 

 les fleurs masculines. En effet de ces' fleurs fermees non-entourees 

 de petits sacs de papier ou de toile, naquirent sur quelques plantes 

 hybrides des fruits renfermant de graines ä pouvoir germinatif. 

 Si c'etait le cas le fruit etait normalement developpe; c. ä d. on 

 n'obtenait jamais des fleurs fermees ä fil de plomb des fruits ren- 

 fermant quelques graines developpees ä cöte d'un grand nombre 

 de graines vides. Les plantes se developpant de cette graine obtenue 

 sans pollinisation ne furent pas toutes identiques, on y constata 

 une disjonction qui fit penser ä une disjonction mendelienne qui 

 demontre ä l'avis de l'auteur que les graines seraient nees par 

 Parthenogenese, non par apogamie. De cette maniere serait prouve 

 le premier exemple de Parthenogenese dans les plantes superieures. 



M. J. Sirks (Wageningen). 



Halsted, B. D., Degenerate plants. (Journ. of Heredity. VIII. 

 p. 270—276. 1917.) 



In some crosses of varieties of muskmelons, pepperplants, 

 eggplants, beans, sweet com the writer has obtained in his F 2 gene- 

 rations many abnormalities, extreme variants frequently either 

 dwarfs or giants and in both cases lacking reproductive power. 

 These observations have been drawn from the records of breeding 

 work that has been carried on for other purposes than the parti- 

 cular study of degenerates. It seems to the writer that the degene- 

 rates, as they have been used in his work, are not forceiul as 

 compared with the normal type. The appearance ofunfit individuals 

 seems to result from the breeding together of kinds that are not 

 congenial because of one or more of many possible reasons. Such 

 unions are forced and the greater the lack of consanguinity, within 

 the comparatively narrow ränge of possible union, the larger the 

 number of defectives. These misfits belong to the two extremes of 

 a large series of types, namely those that show from the Start a 



