454 ORIGINAL ARTICLES. 



since appealed separately, is of enormous length, occupying about 

 150 quarto pages. Only a small portion of it, however, relates 

 directly to the simple question of the existence, or non-existence, of 

 fructification without impregnation. The author expressly contra- 

 dicts the theory advanced by Klotzsch as to the nature of the body 

 within the seeds of Ccelebogyne. He says : "I can confidently re- 

 " affirm, and prove at any time by sections of seeds in my possession, 

 " that the embryo-formation of Ccelebogyne which I have observed 

 " and described, fulfils all the conditions necessary to constitute a 

 " veritable embryo, and agrees in its essential features with that of 

 " the other Euphorbiaceas." In a later part of the essay some 

 remarks are given under the head "Weitere Zeugnisse fur die 

 Parthenogenesis," of which the following is a short account. Some 

 observations on individual plants given by Euprecht, Tenore, Lecoq, 

 and Jacquemont are noticed, the author stating that he was un- 

 willing to pass them over entirely, although (he adds), as merely 

 special instances, little importance may be attached to them. Dr. 

 Braun then refers (as bearing upon the question of parthenogenesis) 

 to those cases of fructification called by Gartner Fructifcatio spuria, 

 in which fruit is formed, and even seeds also ; the latter being appa- 

 rently perfect, but containing no embryo. Instances of this occur 

 in Datisca, Adelia, the Cycadese, and the Conifers ; and give rise to 

 the question, whether the unimpregnated germinal vesicle disappears 

 without undergoing any development ; or whether the development 

 progresses to a certain extent, and is then arrested. Dr. Braun con- 

 siders this point deserving of investigation, as, in his opinion, it is 

 not improbable that, besides perfect parthenogenesis, there may exist 

 indications of parthenogenesis, as has been observed in the animal 

 tino-dom. The above question, he adds, is connected with the further 

 ones ; 1, whether or not, speaking generally, the formation of seeds 

 and fruits depends upon the development of the germinal vesicle into 

 an embryo; and, 2, whether, when impregnation occurs, it acts directly 

 only upon the development of the germinal vesicle into an embryo, 

 and thus indirectly upon the formation of the surrounding parts ; or 

 whether impregnation acts upon the entire ovule, or even upon the 

 ovary itself. Observations, he says, are wanting as to the well-known 

 cases of fructification without seeds which occurs in certain cultivated 

 varieties of Citrus, Pyrus, Cydonia, Vitis, Arlocarpus, Ifnsa, and 

 Ananassa. It should be ascertained in what stage of development 

 the ovules fail, and whether the formation of these seedless fruits is 

 in all cases independent of impregnation. 



Having regard to the cases in which parthenogenesis has been 

 noticed in the animal kingdom, Dr. Braun observes that it might be 

 expected to play a more important part amongst cryptogamic, than 

 amongst phamogamic plants. He adds, however, that this question 

 is surrounded by many difficulties, and that he can do no more than 

 make a few suggestions on the subject. He alludes, in the first place, 

 to the ferns, in which he considers that the constant reappearance 



