6 BRITISH FERNS. 
can, at least, direct his attention to the mode of fructi- 
fication, and to the fruit produced. In Ferns, strictly 
so called, it is dorsal ; that is, scattered in clusters or 
patches on the back of the frond. These patches are 
generally accompanied with an integument called the 
Indusium, which, at the period of the maturity of the 
seed, bursts open, sometimes towards the nerves, and 
sometimes towards the margin; but in plants of a 
similar habit, uniformly in a similar manner. The 
merit of this discovery is due exclusively to Sir J. E. 
Smith, who found it to be a most decisive criterion for 
the determining of natural genera, and the only sure 
ground on which the botanist can rely. When this 
integument bursts, the fruit, now ripe, escapes, which is 
for the most part a capsule surrounded by an elastic 
and jointed ring opening transversely, and discharging 
the enclosed seed or sporule, which is a small and 
minute globule, discoverable only by the microscope, 
and capable of giving origin to a new plant. Ferna 
were raised from the sowing of their seeds in 1789, by 
Mr. J. Lindsay, of Jamaica, as also by Mr. J. Fox, of 
Norwich, about the same time." 
From that time Ferns began to obtain more notice 
from gardeners, and there is now no order of plants of 
which the propagation and culture are better understood. 
