F E 11 N S;
B R I T I S H A N D EXOT I C.
ASPIDIEaE. j . S m it h .
In many instances the only diilerence between PolypodiecB
and Aspidiece is confined to the former having no indusium,
whilst the latter is furnished with an indusiuin; this, however,
is sometimes very small, and at others so soon detached from
the sori, that fronds must be examined, the one with a
microscope and the other at an early stage, in order that the
difference from Polypodiece may be detected.
Mr. Smith remarks that there are above two hundred described
species of Aspidiece.
Aspidiece is distinguished from Aspleniece mostly by having
circular instead of lateral sori, and when the sori are lateral they
are attached across the venule, instead of longitudinally in the
direction of the venules as in Aspleniece.
Sori circular, with one or two exceptions, where oblong. They
are intramargiual, and have a special indusium, which is either
orbicular, produced from the centre, (central,) or reniform or
cucullate, produced from the interior side of the sporangiferous
receptacle, (lateral,) or occasionally attached all round the
receptacle, and including the sporangia, (calycifonn.)
Mostly moderate-sized Ferns.
VOL. VI. B