M. E. Kegel un PartJienogenesis. 101 



of the present century, deny the necessity of fecundation, but 

 these were solitary voices (Schelver and Henschel*). The 

 theory of fecundation, the practical proof of it (the production 

 of hybrids), was assumed to be a settled fact, and up to our own 

 time underwent a continually fuller development. 



A few voices were here and there raised, not against the 

 theory of fecundation generally, but for the proposition that in 

 certain plants a true embryo might be formed without fecunda- 

 tion, where this was hindered ; in other words, it was assumed 

 that, " Normally J the embryo is developed in a seed only under the 

 influence of fecundation. But if the fecundation is prevented, in 

 certain cases an embryo may be nevertheless developed." Strictly 

 speaking, therefore, it was assumed that the male sexual organs 

 of plants are wholly superfluous structures. 



But this assertion was made always in reference only to parti- 

 cular plants, and indeed to the same with which Spallanzani had 

 experimented in the year 1786, namely Hemp and Spinach f- 

 How inexact Spallanzani's observations must have been, appears 

 from the fact that he obtained ripe seeds even from Basil from 

 which he had removed the anthers, also from Water-melons, &c. 



On these latter and similar plants, on which it is easy to ope- 

 rate, there exist a number of direct experiments to show that the 

 prevention of fecundation hinders the production of seeds capable 

 of germination; these and similar observations have been re- 

 peated subsequently by persons who were wholly destitute of the 

 knowledge requisite for an exact experiment. On the other 

 hand, Bernhardi, an otherwise very exact observer, repeated 

 Spallanzani's experiments on Hemp J, and obtained exactly 

 similar results. 



This question then sank to rest again ; Bernhardi^s observa- 

 tions were explained by assuming inaccurate observation, or the 

 formation of a bud in the seed. 



In 1841, J. Smith § made known his observations on the 

 production of seed by Cmlebogyne ilicifolia, which was stated to 

 perfect all its seed without any fecundation. At the same period 

 Lecoq asserted the occurrence of Parthenogenesis in a host of 

 plants. From his superficial observations he drew the conclu- 

 sion that all annual plants with separate sexes could form per- 

 fect seeds without fecundation. By such a wise contrivance, 

 nature prevented the dying-out of such plants. 



* Henschel, von der Sexnalitat der Pflanzen, nebst einem historischen 

 Anhange von Dr. F. J. Schelver. Breslau, 1820. 



t Spallanzani, Experiences pour servir a I'Histoire de la Generation des 

 Animaux et des Plantes. Geneva, 1785. 



Otto und Dietrich. AUg. Gartenzeitung, 1839, pp. 32/, 329. 

 Trans. Linntcan Society of London, 1841, p. 609. 



