16 
BRITISH FERNS. 
species, and under different states of heat and moisture, 
but it is not a matter of such long patience as is often 
supposed. Some remain several months before they make 
their green scales, and some produce them with com- 
parative rapidity. Gymnogr omme leptophylla , being more 
or less an annual fern, requires to be continually raised 
from spores, and it germinates with great ease and rapi- 
dity ; it will even sow itself and spring up spontaneously 
in neighbouring pots in the greenhouse or among the 
mossy undergrowth in a Wardian case. Pteris tremula 
and serratula have the same obliging tendency to mul- 
tiply themselves. Loudon relates facts regarding the 
propagation and development of cultivated ferns which 
have come under his own observation. Specimens of 
Gynmogramme tartarea were brought from Jamaica, and 
the spores carefully distributed over a prepared vessel, 
on July 10, 1817. The spores germinated, passed through 
their Liverwort-like stage, put up true fronds, and pro- 
duced spores again by August, 1818, and by Septem- 
ber, 1819 , a series of grandchildren had ripened spores 
for another seed-time ; thus, each generation required 
thirteen months for full development. The spores 
of ferns, being so extremely minute and delicate, are of 
course subject to all the dangers that threaten the life of 
other seeds, and to some peculiar to themselves; in fact, 
it is a matter of surprise to all who know the extreme 
care required in raising seedling plants under cultivation 
that any such should arrive at maturity in their native 
localities. This can only be accounted for by consider- 
ing the immense number of spores produced by each 
plant, allowing thousands and tens of thousands to perish 
for want of suitable soil and shelter, for every spore that 
reaches perfection in its development. When the seed- 
