THE NATURAL CONDITIONS OF PLANTS. 47 
Hymenophylla require much sun. This will be 
a fitting place to make mention of a small but 
most interesting bottle which I received in Oc- 
tober 1837, from Mr. Newman, sup erinten dent 
of the Botanic Garden in the Mauritius. The 
bottle was filled with two or three specimens of 
a small species of Gratiola, and of Cotala, and 
lightly covered with painted canvas. The plants 
were in full flower. I placed them in a window 
with a southern aspect : they remained in vigour 
for six or seven weeks, when they successively 
declined and perished without ripening any seed, 
in consequence of the too great humidity of the 
soil. Before this took place, I observed, as in my 
first experiment, several seedling ferns making 
their appearance between the mould and the side 
of the glass, and therefore allowed the bottle to 
remain in the same situation, which it has occu- 
pied to the present time, the covers having been 
twice renewed in consequence of decay. It is 
now a very interesting object. The upper part is 
filled with fronds of two species of Adiantum, and 
the lateral surface of the mould is coated with 
seedling ferns in all stages. 
We may learn a few useful lessons from this 
little bottle. We see how abundant the seeds of 
ferns are, and how easy it would be to obtain 
many species from distant countries by collecting 
