26 HISTORY OF BRITISH FERNS. 
the young growth as soon as it begins to form, but is appa¬ 
rently not necessary as a means of exciting it. It matters 
little in what way the principal condition above mentioned 
is supplied. In hot-houses and confined situations, con¬ 
genial to ferns, the plants shed their spores freely; and 
the latter germinate on the undisturbed soil, or on any 
damp surface with which they come in contact, sometimes 
even on the upright sides of the pots in which the plants 
are growing, if these are so circumstanced as to remain 
continually damp. They grow very "readily on the rough 
surface of a piece of sandstone-rock, just kept moistened by 
water constantly, but slowly and gently, dripping upon it. 
The most convenient way, however, to raise Ferns from 
the spores, where cultivation is the object, is to sow them 
on the surface of moist, loamy soil, in pots of convenient 
size, the surface of the soil being kept an inch or more 
below the level of the pot rim, so that a piece of flat glass 
may be laid over the top, to secure a close and constantly 
moist atmosphere, and prevent rapid evaporation from the 
soil. 
The pots should be nearly half-filled with small pieces 
of broken potsherds or of broken bricks, and the soil itself 
should be used rather coarse than fine, the surface being 
