44 
CHOICE BRITISH FERNS. 
producing crosses combining the characters of specially fine 
varieties. An instance of one of Mr. Clapbam’s successes in 
this direction is seen on Plate Y., Pig. 12, which shows an 
intentional cross between a beautifully - crested Polypody 
{Polypodium vulgare hijido cristatum, Pig. 2) and a very 
finely-divided one (P. elegantissimum>, Pig. 10) ; the result being 
not only the transference of the characteristic cresting of 
the former to the latter, but also 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. 
