81 



Riccia M. Lindenberg found the number 13 predominant, 

 while M. Mohl considers 14 to be the general rule. 



The following observation was made on the germination of 

 the spores of R. crystallina, glauca, andfluitans. In the first 

 fourteen days merely a swelling of the margin of the spores 

 could be perceived; between the fourteenth and twentieth days 

 this margin expanded at one, or simultaneously at several 

 places. The expansions finally formed cells, but the further 

 development could not be observed. The fructification of the 

 spores is effected by the turbid fluid which proceeds from the 

 apertures of the anthoid organs, and flows over the surface of 

 the fronds. 



M. Martens* has observed in the Botanical Garden of Lou- 

 vain, a hybrid between Gymnogramma calomelanos and G. chry- 

 sophylla, to which Bory de St. Vincent f proposes to apply the 

 name of G. Martensii. At the same time the latter gentleman 

 observes, that this hybrid formation appears to occur quite 

 commonly in nature, for he had received several well-preserved 

 specimens of this plant through I/Herminier from Guade- 

 loupe, where it grows among the two above-mentioned Gym- 

 nogrammce. He also enumerates several other ferns that 

 might be considered as hybrids, which it is true is merely 

 founded on suppositions, to which however I am partially in- 

 clined to assent. 



The experiments on the artificial propagation of plants by 

 leaves have also been extended. In a memoir by E. Otto, 

 W. Brackenridge, C. Plaschnick, and C. BoucheJ, gardeners 

 in the Royal Botanical Garden of Berlin, several new observa- 

 tions of the kind are enumerated ; the work originated in a 

 prize question which had for many years been proposed by the 

 Horticultural Association, as to the best mode of increasing 

 plants by cuttings, and it obtained the prize as the best of 

 the answers communicated. The memoir is divided into four 

 parts, which treat of the propagation of plants by true cut- 

 tings, by root cuttings, by gem cuttings, and by leaf cuttings. 

 In the latter section it is stated that several species of Theo- 



* Hybridite dans les Fougeres. L'Institut, 1837, p. 228. 

 f L'Institut de 1837, p. 280. 



I Verhandlungen des Vereins zur Befdrderung des Gartenbaues in den 

 Konigl. Preuss. Staaten. xiii. I 8 Heft. Berlin, 1837, p. 7. 



G 



