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this possibility may be utilised to the best advantage. Polypodium 
Schneiderii is, I think, eloquent with two possibilities of extreme 
value. The one is that of enhancing the simple beauty of 
many exotics by alliances with the highly ornate forms which 
(.ur British hardy species have assumed, both under purely 
natural conditions as wild finds and under selective culture of 
the progeny which they have yielded. The other is the 
increased capacity of exotics, so hybridised, to withstand low 
temperature, due to the infusion of hardy blood. In Ferns, 
thanks to the curious fact that the prothallus, or green scale 
u p on which the flower homologues are produced, is almost 
constant in size throughout all species except the Filmies, the 
minutest species and the largest Tree Fern commence their 
career under practically identical conditions, and crossing and 
hybridisation therefore are not limited as in flowers by incom 
patibilities between length of stigma and size of pollen. Hence, 
so far as size is concerned, there is no bar, and the smallest 
may be allied with the largest if specific or generic differences 
be not too great. Consequently, though our British Spleen- 
worts are all of comparatively small growth, their varietal forms 
may presumably be imparted to many of the grand large- 
growing exotics, and the task is the better worth attempting, 
as the genus is peculiarly exempt from the tendency to form 
tasse led or crested varieties, though examples of such occur 
among our native species, and thus afford fair starting-points 
for hybridising purposes. Scolopendrium vulgare, curiously 
enpugh, though extremely closely allied to the Asplenia, and 
capable, as we have seen, of a definite alliance with them, is, 
on the other hand, one of the most variable Ferns in the world, 
and hence, taking the varieties of this species and the tasselled 
forms of Asplenium trichomanes and A. adiantum nigrum, 1 
would suggest systematic admixtures of the spores of these 
with a number of the plain-fronted exotic Asplenia, and 
particularly with A. nidus avis. This last has recently given 
us one curious wild semi-cristate sport, A. n. a. multilobatum, 
indicating great capacity for variation; and considering its 
extremely close agreement in structure with Scol. vulgare and 
the alliance above cited of th s latter with Asp. ceterach, 1 feel 
confident that with perseverance we might not only obtain 
handsomely tasselled Bird’s-nest Ferns, but also, in conjunction 
with some of the fertile forms of S. v. crispum, frilled ones as 
well. That beautiful Hart : s-tongue, for instance, S. v. laceratum, 
with broad sagittate, tasselled basal lobes, deeply cut pinnatifid 
fronds, tasselled heavily at their terminals, would be a splendid 
mate, and the hybridist who mated the twain would certainly 
not repent the trouble taken. This field is a very wide one, 
