Dr. L. Radlkofer on hue Parthenogenesis in Plants, 209 



grains. The impossibility of the action of Hemp-pollen/'^iit 

 least, was, however, really secured by the circumstance that the 

 period of the experiment did not coincide with the epoch of 

 flowering of the Hemp cultivated in fields and gardens. For 

 the absence of any abnormally developed male flowers from 

 the plants used, we have the testimony of the eyes of Naudin 

 and Decaisne. I owe it to Decaisne^s kindness that I myself 

 had an opportunity of seeing one of these plants. Nothing 

 could be stranger than their appearance : the plant was just 

 ripening its fruits; these ripening fruits were, however, still 

 crowned by long feather-like stigmas, in which there was no 

 trace of commencement of withering, — and this at an epoch 

 when the ovaries of the same plants which have been exposed 

 to the action of pollen have long lost their stigmas. 



The same phsenomenon was observed in plants of Mercurialis 

 annua, which Thuret of Cherbourg raised in a closed chamber, 

 excluding males, for the purpose of testing Naudin^s experiments. 

 Here also, giving not a little peculiarity to the whole habit_, the 

 highly developed fruits were still, when they had attained nearly 

 their full size, furnished with unwithered stigmas, which had 

 enlarged in proportion with the growing ovaries ; while in such 

 specimens as vegetate under regular conditions, in company 

 with male plants, the stigmas are very transitory, and always 

 wither and fall off" when the expansion of the ovary has scarcely 

 begun. Dissection proved that the seeds of those plants raised 

 in closed chambers contained embryos. 



This unusual and remarkable behaviour of the stigmas cannot 

 be ascribed to any other circumstance than this, — that they had 

 not been exposed to the action of the pollen ; that their cells had 

 not been called upon to give up any part of their contents for 

 the nutrition of the tubes growing from the pollen-grains. The 

 researches on Cannabis and Mercurialis complete the above- 

 mentioned observation of the peculiar behaviour of the stigmas 

 in Ccelebogyne, in a manner calculated to remove completely any 

 doubt that might still prevail in that case. This behaviour of 

 the stigmas is the surest evidence that the exclusion of the pollen 

 in the experiments on Cannabis and Mercurialis, and, in like 

 manner, on Ccelebogyne, was not merely probably but actually 

 complete ; and we are no longer compelled, in making certain of 

 this, to trust to the supposed sufliciency of the artificial means 

 of exclusion, nor to the belief in the impossibility of our eyes 

 being deceived. 



Thu^, then, is proved the existence of Parthenogenesis in the 

 vegetable kingdom. 



Circumstances, unfortunately, did not allow of my giving the 

 same negative testimony, as in the case of Ccelebogyne, as to the 



Aim. ^ Mag. N. Hist. Ser. 2. Vol. xx. 14 



