35G Proceedings of the 



in so many plants, are very thin and fragile, remain empty, and are 

 compressed by their natural spring. This is the reason that so many 

 compound and syngeneceous flowers, such as the malvacea, the con- 

 volvuli, &c., close during the night, and even when the sky is cloudy. 

 AVhcn, on the contrary, the sun is radiant in the horizon, the heat 

 and light soon recall an abundant sap into the branches, and the 

 petals of the flowers open. Thus the flowers of the wild anemone, 

 when closed by the cold, will, if brought into a warm place, or even 

 if their peduncles are plunged into warm water, so as to occasion an 

 ascent of the sap, unfold their petals, and resume their primitive 

 vigour. 



The same principle accounts for the opposite phenomenon observed 

 in night-flowers : they are closed in the day, because the heat and 

 light of the sun are too powerful for the frail texture of certain petals, 

 and evaporate too much of the sap and nutritious juices which fill 

 their vessels. But in the freshness of the evening, when the sap and 

 juice, not being so powerfully evaporated, rest in greater quantity in 

 the tissue of the plants, they dilate those vessels, and the flowers re-open.' 

 The reporter remarked that this theory is precisely similar to that of 

 Adamson ; but in order to admit that it is strictly true, it must be 

 established that the nocturnal plants, which are represented as being 

 liable to be too powerfully acted on by the solar rays, are always 

 more frail and delicate than those diurnal ones which only flourish 

 under the strong influence of the sun. This, however, is not the case, 

 since the cistus, the aquatic ranunculi, the cdemacea, the hydro- 

 charices, and certain of the cruciform genus, which are diurnal 

 plants, are flowers of extreme fragility and delicacy, and ought, 

 therefore, according to the theory, to have their sap so completely 

 evaporated, that their petals would be closed all day, and only open 

 at night. The reporter, however, commended the industry of M. 

 Viret, and recommended the Academy to request him to continue to 

 communicate the result of his experiments and observations on the 

 closings of the petals or flowers, as likely to tend to the establish- 

 ment of a theory not liable to the objections raised to that now put 

 forth. The report was adopted. 



Sclf-fccundation. At the same meeting, M. Bureau de Lamalle 

 presented a piece of female hemp, which he believed to have been 

 fecundated without having been subjected to the influence of any 

 male hemp. He remarked that, although self-fecundation was a prin- 

 ciple which could not in any case be admitted, he had seen reason to 

 believe that some plants possessed the property belonging to some 

 insects, of being fecundated for several generations in advance, by 

 which means the later generations would present the appearance of 

 fecundation without the intervention of a male ; whence has arisen 

 the idea of self-fecundation. 



Flowers of the Reseda. On the 5th of September, M, Auguste 



