134 PLANT HYBRIDIZATION BEFORE MENDEL 



The term "disordered variation" (variation desordonnee) is 

 probably employed by Naudin for the first time in his paper of 

 November 21, 1864, "De I'hybridite consideree comme cause de 

 variabilite dans les vegetaux." (4d, p. 157.) The use of the term 

 arose from experiments in crossing, reciprocally, Datura laevis 

 and ferox. In 1863, sixty individuals were grown of the cross 

 laevis X ferox, and seventy of ferox X laevis. Of these plants, 

 all of which came to full development, he says, 



". . . they have been so perfectly like one another that the two lots 

 would have been easily taken for a single one." (p. 155.) 



This result he considers a new confirmation of the conclusion 

 already announced in his memoir presented to the Academy in 

 1863, (4c) : 



". . . that there is no sensible difference between the reciprocal hy- 

 brids of two species, and that in the first generation the hybrids of the 

 same derivation resemble one another as much as do the individuals of 

 the same pure species, issuing from the same sowing." (4d, p. 155.) 



"In this first generation," he adds, "the entire collection of the hybrid 

 individuals of the same origin, however numerous they may be, is as 

 homogeneous and as uniform as a group of individuals would be of an 

 invariable species, or of a pure and clearly characterized race." {ib.^ 



P- 155.) 



According to Naudin's statement, although both the parents 

 had white flowers and green stems, the hybrids of the first gen- 

 eration were all characterized by violet flowers and brown stems, 

 and with spiny fruits. This development Naudin ascribes to an 

 extension, over the whole plant of the hybrid, of a character 

 which was found to appear in a rudimentary way in the stems 

 of the seedlings of D. ferox, which, at the time of germination, 

 are stated to be of a deep violet-purple, extending from the root 

 to the cotyledons, where it suddenly stops, giving way to a clear 

 green tint. In the hybrids of the first generation : 



". . . it takes on an enormous increase, reaching all parts of the plant, 

 and manifesting its action especially upon the flower." (p. 156.) 



In 1864 the second generation of plants of the two reciprocals 

 was grown. Nineteen plants were raised of D. ferox X l^e'vis, 

 and twenty-six of D. laevis X ferox. 



"To the great uniformity [i.e., of the first generation! there succeeded 

 the most astonishing diversity of forms, a diversity which is such that, 

 of the forty-five plants which compose the two lots, one would not find 

 two which exactly resembled each other." (p. 157.) 



