1900 | BRIEFER ARTICLES 415 
each of its few stations by means of a natural hybridization? The 
rarity of its occurrence is a matter of fact; and, granting the hybridity 
supposition, it is evident that from the resulting plant of a single 
cross excessive multiplication is hardly to be expected, be the spores 
ever so fertile. Evidently much would depend on the environment, 
and it is easy to assume that the Havana station has proven most favor- 
able, the Virginia locality rather less so, and the ,remaining stations 
barely capable of supporting their foundlings. In view of anything 
like conclusive evidence at the present time it is obviously impossible 
to settle the contention ; my effort has been merely to bring together 
the related facts known, and to suggest again the possibility or perhaps 
the probability of such a solution. 
It is evident, as has been both affirmed and denied, that the burden 
of proof rests with those who claim hybridity for the fern; it remains 
for the sponsors for that theory to prove their contention by actual 
demonstration. It can be done only by painstaking artificial crossing 
of the supposed parents; and I am inclined to the belief that this is 
possible. It is easier, admittedly, to proclaim the hybridity of the fern 
a myth, its abundance at Havana sufficient evidence that it is a distinct 
Species, the scattering plants mere relics of a more general northerly 
distribution, and all else mere speculation; but it appears to me that 
the invariable presence of both supposed parents, the anomalous 
appearance and peculiar morphology of the fern, its usual occunrende 
singly and in this connection its very rarity embrace a ae 
of hybridity too patent to be ignored, and of sufficient interest to 
warrant careful cultural experiments—— WILLIAM R. Maxon, J. S. 
National Museum, Washington, D. C. 
