[1]Milde indicates several other unimportant variations; and Hooker &
Baker have as varieties of this species the East Indian _Aspidium
cochleatum_, and _Aspidium elongatum_, from Madeira and the Canary
Islands. The latter they give as occurring also in the southern
United States, evidently supposing it to be the long-lost _A.
Ludovicianum_ of Kunze. For abundant synonymy of _Aspidium Filix-mas_
the student is referred especially to the works of Hooker, Milde,
Mettenius and Moore, as quoted above.
[2]See the “Flora of New York” for some figures of laciniated and forking
fronds.
[3]Prof. Amos Eaton, grandfather of the present writer. Eaton’s “Manual
of Botany” went through eight editions from 1817 to 1841.
[4]I find one or two instances of a slight enlargement of the apex, as if
there were an attempt to form a proliferous bud.
[5]“In _O. sensibilis_ the sori are borne on the middle of the vein, and
consist of a tough cylindrical receptacle, three or four diameters in
height, bearing sporangia thickly all over its surface, and covered
when young by a delicate hood-like indusium, attached half-way or
more around the base of the receptacle on the inferior side, and
having the crenulate-margined opening toward the apex of the segment.
At an early stage the blackberry-shaped sorus is almost entirely
covered by the indusium, which resembles a closely drawn cowl, but
with the growth of the sporangia it is thrown back, or rent, and soon
disappears, the sori becoming confluent. The receptacle is very
persistent, and may be seen, covered with the stalks of the
sporangia, in the dried last-year’s fertile fronds, which are always
found where the plant grows.”