spores. 
35 
case, the result is tlie transference not only of the 
characteristic cresting of the former to the latter, 
but also of its peculiarities to the otherwise normal 
fronds which the latter is in the habit of producing* 
occasionally — a feature which, of course, places the 
cross beyond a doubt. It does not, however, follow 
that operations of this kind are always successful, 
and failure at a first experiment must not prevent 
another attempt being made. 
It is well nigh impossible to trace the parentage 
of certain crested varieties. Indeed, they can only 
be described as natural sports or accidental varia- 
tions in seedlings, which may possibly later on 
produce numerous forms more or less crested, as is 
now the case with Pteris f^errulata. As a general 
rule it may be taken that when the original form has 
once varied, it has a greater tendency to vary again. 
Propagation by spores is not always the quickest 
means employed for the reproduction of certain 
snecies. Filmy Ferns, for instance, are exceedingly 
slow in producing their first fronds, and Hymeno- 
vhyllum demissum 717 tens and H. pidcherrimum have 
been known to remain five years in the prothallus 
state. Hymenophyllums, therefore (and with them 
Trichomanes), must not be included amongst Ferns 
which are best propagated by sDores : on the contrary, 
they increase more rapidly by means of division. 
Todeas, however, which belong to the same section, 
can only be propagated by spores. For a long time 
the stock of these lovely pbmts was only kept up by 
frequent importations. 'Now seedlings are freely 
raised, though they require several years of careful 
and constant nursing. 
All growers for market raise their Ferns from 
snores : but their mode of procedure differs materially 
from the one recommended above. Their aim is not 
the formation of a collection, but simply the cultiva- 
tion of showy species and varieties. IN'ecessarily, 
therefore, they restrict their attention to a few 
genera, such as Adiavtnm, Pteris, A'ephrodiKiii, 
Aspidium, and Poly podium, and even of these they 
only grow the more vigorous, bringing them to 
D 2 
