426 Meyen's Report for 1839 on Physiological Botany. 



given. Finally, the curious increase by continued regular di- 

 vision was explained in the case of that small Alga which I 

 have denominated Merismopedia punctata, a plant which 

 Ehrenberg has erroneously reckoned among animals. The 

 regular position of the small ellipsoidal cells of this plant in 

 fours instantly strikes the observer, and the propagation of 

 these takes place by their regular division, which by obser- 

 ving different individuals may soon be seen in all its different 

 stages. The new cells group themselves always in fours, and 

 are surrounded by a tender gum-like substance. 



In the Botanical Society of London* Mr. Daniel Cooper 

 made known some experiments he had made to see whether 

 coloured fluids entered into plants which were watered with 

 them ; the experiments were made without the author's being 

 aware of what had been done previously. Three pots with 

 large beans were taken, two were filled with mould and one 

 with common sand, and all were watered with the same quan- 

 tity of fluid, but the water which was used for the pot filled 

 with sand was strongly coloured with madder. The result 

 was that the coloured fluid did not pass into the plants, 

 which were not at all changed by the operation. Mr. Cooper 

 had placed one of the pots with mould in a dark place ; he 

 brought the grown-up plant into the light, and saw that the 

 leaves first became lax and then died ; and the same was the 

 case with the other pot, which had been allowed to stand in 

 the open air and was then brought into the dark ; in this case 

 also death finally ensued. 



At the same time Mr. Cooper made known an observation 

 of Mr. Wilkinson, who had observed that a potatoe which 

 had fallen into a well twelve feet or more deep, grew out of 

 it in order to reach the light. According to other observa- 

 tions, the length of a potatoe stalk grown in a cellar has been 

 found to be twenty feet, on attaining which length it reached 

 the window. 



Phenomena of Generation in Plants. 

 1. In the Phanerogamic Plants. 



In the former Report I could only give a very imperfect 

 account of M. Wydler'sf research on the formation of the 

 embryo in the genus Scrophularia, for up to that time the 

 treatise was unpublished. M. W. made his observations on 



* Proceedings of the Bot. Society of London, &c. With Plates. London, 

 1839. 



f Recherches sur la Formation de l'Ovule et de PEmbryon des Scrofu- 

 laires. — Bibliotheque Universelle de Geneve, Oct. 1838. 



