70 



of conversion of a young seta into a partially leafy stem. The sup- 

 posed proof of such a conversion is what is well known by every prac- 

 tised bryologist to be a phenomenon of universal occurrence whenever 

 a moss is removed from a free, dry atmosphere, to one that is confined 

 very and humid. It is still more observable when the moss is shut up 

 in the dark. Indeed, it is nothing more than what is called etidlation,, 

 and as a consequence of such treatment, the young branches or inno- 

 vations in Mr. Quekett's specimens, which would in ordinary circum- 

 stances have been very short, and only developed at a later period, 

 have been suddenly drawn up and attenuated until the branch and the 

 definite number of cellules composing it have been elongated several 

 times their usual length. Of course such a stimulus to luxuriant 

 growth of the stem must operate as a check to the growth of the fruc- 

 tification, and it is generally observable that in such cases the fruit is 

 abortive. This happens in an unusually wet season to most mosses, 

 without the intervention of a Warcrs-case. 



W. Wilson. 



Warrington, February 11, 1851. 



On a Supposed Netv British Species of Adianlwii. 

 By W. Wilson, Esq. 



I SEND full-grown fronds of an Adiantum from roots which have 

 been in cultivation upwards of ten years, and which were gathered in 

 the Isle of Man, by my friend Mr. T. G. Rylands. It differs very 

 considerably in appearance from the ordinary form of A. Capillus- 

 Veneris, and may perhaps be a different species. If compared with 

 the figure in ' English Botany,' it will be seen that the frond is narrow 

 and oblong, by no means flabelliform, and the branches, instead of 

 being set at an acute angle, are widely spreading. The pinnules do 

 not taper gradually into the foot-stalk, and seem to be of quite a dif- 

 ferent shape from those of the Arran specimen. The characters pre- 

 sented by the fronds sent are constant in the plants under cultivation. 

 I may here mention, that when I received the roots they were hastily 

 planted in a common garden-pot, and were afterwards much neglected, 

 until I thought they had quite perished for want of water. If they 

 had not been more than usually tenacious of life such would have 

 been their fate ; but by careful nursing they were saved, and have 

 ever since grown vigorously in a greenhouse, without artificial tempe- 



