Tlate 1 .
cognized at a glance. The mark by which it is known is
th is:—the back of every frond is covered by densely-
packed, brown, pointed, chaffy scales. Among these scales,
and concealed by them, lie the elongate sori, which are
anomalous, in regard to their relationship, in having no
indusium. The affinity of Ceterach is without doubt with the
Asplenium-like Terns, and this being the case they ought
to have an indusium; the Polypody-like and Acrostichumlike
Perns only, among the dorsal groups, wanting this
cover to the sori. No indusium, however, exists here,
unless it be represented by a kind of membranous ridge,
which exists on the receptacles just behind the sori, and is
the part which has been called an indusium. The probability
is, that it does represent that organ, which is not
largely developed in consequence of the presence of so
dense a covering of scales, these not only serving the purpose
of a cover to the sori, but perhaps, from their crowded
position, preventing its proper formation.
The name Ceterach is an alteration of the word Chetherah,
which was applied to this plant by Persian and Arabian
medical writers.
Ce t e r a ch o f f io in a r um , Willdenow.—Ttie Scaly Spleenwort.
(Plate I. fig. 1.)