ON THE FORMATION OF SEEDS. 55 



" The observation of Smith on the Ccelebogyne gave me the first idea 

 of noting what would become of isolated female Mercurialis. A few 

 very young plants, placed in pots before the appearance of their flowers, 

 were put, some in a greenhouse, others in the small room just spoken 

 of. The precautions were such, especially as regards the latter, that it 

 is impossible to admit they could have received pollen of their species. 

 All these plants, eight in number, produced an immense quantity of 

 female flowers, of which a part, perhaps a fiftieth, bore fruit well formed, 

 and containing seeds which germinated perfectly this year. 1 can also 

 affirm that these plants did not produce any male flower. 



" As a counter-proof to this experiment, I took away from two plants 

 of Ricinus (of which one was found near similar plants, and the other 



distant enough to be considered out of the reach of their pollen) all the 

 male flowers which were there, and which were in different stages of 

 progress. All the female flowers fell off successively, without being 

 able to set fruit ; and yet one could suppose, with a certain degree of 

 probability, that the stigmas of one of these two plants might have re- 

 ceived some grains of pollen. Here then are three EupJiorbiacea, of 

 which a monoecious one does not fructify without fecundation, and two 

 others, dioecious, in which seeds are formed undoubtedly without the 

 aid of pollen. 



"I observed, in 1854, in ground close to a wall and palisades, be- 

 longing to the Museum, a female plant of the common Bryony {Bryonia 

 dioica), quite alone in this ground, and which, from thousands of flowers 

 which it had produced, had set and ripened fruit in very great numbers, 

 but in a proportion incomparably less than that of the flowers. These 

 fruits contained well-formed seeds. In November of the same year I 

 had fifteen of them sown in a hothouse ; all came up very well. In 

 1855 this female Bryony fructified as it did in the preceding year, and 

 in the same proportion as it had done in 1856. I have examined the 

 flowers many times, and have never found in them any traces of anthers. 

 We may then suppose that some fruits which it produced each year 

 proceeded from fecundations effected by the intervention of insects. 

 What follows will prove that this reason cannot be advanced. 



" In April of this year I caused to be planted, in the same border 

 where the Bryony was found, a second female specimen, raised from 

 «*ds produced in November, 1854, and which, till then, had remained 

 potted. Doubtless on account of its youth this plant did not devclope 



