737 



a short distance to the west, we descended into Cwm Idvvall, a task 



not without some risk, as the rocks here are very precipitous. We 



afterwards ascertained that we should have proceeded along the ridge, 



nearly as far as Tvvll Du, before descending. On the east side of 



Cwm Idwall, which forms a sort of platform above the lake, were 



Silene acaulis (in tolerable plenty), Thalictrum alpinum, Pamassia 



palustris, and several of the Snowdon plants. 



We have said nothing of the ferns, although often gratified by the 



luxuriant beauty of the commoner and semi-rare kinds. We were not 



fortunate enough to come across Woodsia, Asplenium septentrionale, 



or Polystichum Lonchitis. Our explorations were generally arranged 



so as to accord with a constant progress on our route. Can any one 



give an account of the rarer ferns of the district during the past 



season ? 



A. Shipley, R. Reynolds. 



October, 1852. 



On the Fertility of certain Hybrids. 

 By T. Bell Salter, Esq., M.D., F.L.S * 



Having, some time since, performed some experiments on certain 

 plants, the results of which brought before me some facts at variance 

 with the opinion commonly received regarding the laws of hybrids, I 

 am induced to state them, very shortly, accompanied with a few 

 remarks upon them. 



I would wish, first, to state the now usually received opinions 

 respecting the laws according to which the intermixture of species, 

 and the subsequent perpetuation of the resulting progeny, appear to 

 take place. I cannot better do so than in the words of Professor Car- 

 penter. " The conclusion which has now been attained," writes that 

 accomplished author, " is equally applicable to both the animal and 

 vegetable kingdoms." " In plants the stigma of the flower of one 

 species may be fertilized with the pollen of an allied species ; and 

 from the seeds produced, plants of an intermediate character may be 

 raised. But these hybrid plants will not perpetuate the race ; for 

 although they may ripen their seed for one or two generations, they 

 will not continue to reproduce themselves beyond the third or fourth. 

 But if the intervention of one of the parent species be used, its stigma 



* Read before the Isle of Wight Philosophical Society. 

 VOL. IV. . 5 B 



