H. BOTANY. 355 



H. BOTANY. 



BOTANY OF THE BERMUDAS. 



According to Mr. Moseley, botanist of the Challenger, about 

 one hundred and sixty species of flowering plants were gath- 

 ered by him on the island of the Bermudas, of which only one 

 hundred are certainly native, those from the West Indies hav- 

 ing probably been brought by the Gulf Stream or by cyclones. 

 Seventy-one of the species belong to the Old World, while 

 two are plants hitherto known only as confined to single lo- 

 calities in the United States. 15 A, January 10, 1874, 42. 



VARIATION OF THE RATE OF GROWTH OF PLANTS WITH THE 



TIME OF DAT. 



According to experiments by Trauth upon squash, tobacco, 

 and other plants, the rate of growth varies during the day; 

 the increase being greater from the evening during the night, 

 and attaining its maximum toward daybreak, and then de- 

 clining. Culture, under glass shades, showed that the differ- 

 ence in growth was not due to the increased transpiration 

 during the day, but that the temperature has a considerable 

 influence. The difference in growth of the leaves, in light and 

 in darkness, could not be traced to the number of the cells. 

 21 A, April, 1874, 381. 



ELECTRICAL PHENOMENA IN PLANTS. 



Dr. Sanderson describes some highly curious electrical phe- 

 nomena which accompany the irritation of the plants Dionma 

 muscipida. He states that when the opposite ends of a liv- 

 ing leaf of Dioncza are placed on polarizing electrodes, in mut- 

 ual connection with each other, and a reflecting galvanome- 

 ter of high resistance is introduced into the circuit thus 

 formed, a deflection is observed, which indicates the exist- 

 ence of a current from the proximal to the distal end of the 

 leaf. This current he calls the normal leaf current. If, in- 

 stead of the leaf, the leaf-stalk is placed on the electrodes, 

 while the leaf remains united to it, in such a way that the ex- 

 treme end of the stalk rests on one electrode and a part of 



