450 ORIGINAL AltTICLES. 



on Mereurialis were conducted in a similar manner and with similar 

 results. The Bryonia w T as kept in a room in the Museum at Paris, 

 entirely isolated from all male plants, and yet for three years succes- 

 sively it produced a few perfect seeds. A young plant raised from 

 one of these seeds also produced perfect seeds without apparent im- 

 pregnation, and the number of them when counted, was found to be 

 about the same as that produced by a female plant exposed to 

 the influence of pollen. This result M. Naudin considers to be 

 opposed to the supposition of impregnation by the aid of insects, 

 which however he thinks may possibly have been the case with the 

 Bryonia. 



The plants of Ricinus and JEobalium produced no perfect fruit, 

 and M. Naudin is of opinion that dioecious plants are more apt to 

 produce fruit without impregnation than monoecious ones. In 1857, 

 Hadlkofer published some remarks upon the present subject in 

 Siebold and Kolliker's " Zeitschrift fur. wiss. Zoologie." He assumes 

 the certainty of the absence of male organs in the female plants of 

 Coplebogyne. He examined the young embryo-sacs, in which he 

 found three germinal vesicles, of which sometimes one, sometimes 

 two, or even all three, became true embryos. He concludes that a 

 true parthenogenesis exists in Ccelebogyne ; and he considers this 

 conclusion fortified by the fact (previously noticed by Smith) that 

 the stigma remains fresh until just before the ripening of the seeds, 

 whilst in ordinary cases it withers shortly after impregnation. He 

 states that, although the stigma in Hemp and in Mereurialis withers 

 soon after impregnation, he had noticed its persistence in one of the 

 female Hemp plants experimented upon by Naudin, and in a female 

 plant of Mereurialis annua which had been kept by M. Thuret apart 

 from the male. 



Braun's elaborate essay on parthenogenesis appeared in 1857 in 

 the " Transactions of the Berlin Academy." After referring to the 

 accounts of previous observers, which, before Ccelebogyne was known, 

 had rendered the existence of parthenogenesis probable, he states 

 that the latter plant is one which fulfils the necessary conditions. 

 The observations made at Berlin agreed with those at Kew, as to the 

 fact of the production by female plants of perfect seeds without any 

 process of impregnation. He considers it to be against all proba- 

 bility that any abnormal mode of impregnation, as by the glands, 

 observed by Smith, should exist, and notices in detail some observa- 

 tions made at his request by M. Deecke, as to the mode of origin of 

 the embryo in Ccelebogyne, the result of which Avas to show that the 

 process differed in no way from ordinary embryo-formation as ob- 

 served by Hofmeister, Tulasne, and Eadlkofer. After noticing that 

 Badlkofer's observations differed from Deecke's only in the fact that 

 the former found three and the latter only two embryonic vesicles, 

 Dr. Braun remarks, " These observations lead to the result, that in 

 " Ccelebogyne the germs of new individuals are developed within a 

 " normally constructed female organ of generation without any 



