Occasional Notes. 
A Note on the Genus Chry sodium,, Jee. — Chrysodium 
is the generic name given by M. Fee to the common 
and long well-known plant Acrostichum aureum of 
Linnaeus. Botanists who are opposed to the multiplication 
of generic names on slight grounds include under the 
genus Acrostichum all ferns with naked amorphous sori, 
regardless of the character of their venation and habit — 
the two characters which others have taken to divide 
these plants into several genera. Of the two characters 
by which the former distinguish that genus, the absence 
of an involucre or covering to the sori is, of course, 
because of its broader bearing, the principal ; and I do 
not wish to convey that I regard the character which I am 
about to describe in the sense of a natural indusium as 
this organ is seen in the truly indusiate ferns ; for, in 
classification, that would separate this plant from its 
natural allies; but keeping this in mind I wish to direct 
attention to a very peculiar character which the plant 
possesses that is not shared by other sub-genera of 
Acrosticha, and, in my view, sufficient to justify its 
separate generic recognition. The feature has been 
noticed and described by M. FEE, but it is not well 
known, nor much understood ; and these remarks on the 
subject were written before I became aware that it had 
already been observed. 
If a fertile pinna of the plant in question be gathered 
before it has shed its spores it will be found to present 
a very different aspect on the under side compared with 
