APPENDIX. 
(A) 
Copy of a Letter to David Don, Esq., read before 
the Linnean Society of London, June 4>th, 1833. 
Wellclose Square, June ith 9 1833, 
My dear Sir, 
The difficulty of conveying ferns from 
foreign countries has long been matter of regret 
to the cultivators of that most interesting family 
of plants. About three years ago I was led to 
make some experiments upon the subject, in 
consequence of noticing a seedling of Aspidium 
Filix-mas, and one of Poa annua, on the surface 
of some moist mould in a large bottle, in which 
I had buried the chrysalis of a Sphinx. Curious 
to observe how vegetation would proceed in so 
confined a situation, I placed the bottle, loosely 
covered with a tin lid, outside one of my win- 
dows, with a northern aspect. This cover allowed 
a sufficient change of air for the preservation 
and development of the plants, and, at the same 
