Much confusion exists as to the variety to wliich Sir J. E.
Smith has given the name dumetorum. The upper figure in this
page represents the plant to which the name
is usually applied; it is dwarf, rigid., convex
in every part, and usually of a very dark
green colour, sometimes inclining to brown ;
the masses of thecæ are nearly black. I t
occurs in abundance on the boggy and
mountainous districts of Scotland and Ireland,
and I have seen it, although more
sparingly, in North Wales. Its character
does not vary perceptibly in cultivation. The
fronds labelled dimetonm in the Smithian
Herbarium appear to me to belong to
this plant, hut they are evidently blighted,
or otherwise deformed, and hence it is
very difficult to identify them.
I t fortunately happens that the identical
plants which Sir J. E. Smith described,
and to which he alludes in the English
Flora, as raised from seed, are at present in existence ; they
are in the Botanic Garden of Liverpool,
and are similar to the lower figure in this
page ; the colour is a light and bright
green ; the form is triangular, the size
diminutive, and all parts of the frond,
the pinnæ, pinnulæ, and the lobes or
divisions of the pinnulæ, are concave. • I
have seen the plants in question, labelled
correctly, but not having met with Mr.
Sheppard, the curator of the garden, I
was not aware they were authentic, and
am indebted to Mr. Moore for the information
that they are the identical specimens
described by Smith.
In the fourth volume of the Magazine
of Natural History, page 162, we have
the same plant described and figured by
the Rev. W. T. Bree, under the name
Aspidium dilatatum recurvum. The
wood-cut has been most obligingly
lent me by Mr. Loudon, and is republished in the following page.
In the neighbourhood of waterfalls, and other damp situations,
the plant becomes more elongate and luxuriant, and is then the
Aspidium dilatatum concavum of Babington, a name, by the way,
of great excellence, and highly expressive of the peculiar
character of the plant.
The types of form of this fern may be considered as four.
1. The linear type: erect, rigid, pale sickly green, lateral
margin of the frond nearly linear, figured at page 58, and the
spinulosa of London Herbaria : it is sometimes much narrower,
and the pinnæ point more upwards than in the figure.
2. The dwarf type : dwarf, nearly erect, rigid, dark green or
brown, lateral margins nearly linear, all the divisions having a
tendency to become convex above ; figured at page 60 (the upper
figure) ; this is the dumetorum of London Herbaria.
3. The triangular type : drooping, deep full green ; broadly
triangular, the divisions having a tendency to become convex
above ; figured at page 59 : this is the dilatata of London
Herbaria.—Note. I t is extremely easy to find a complete series
of intermediate fronds connecting these three types of form.
4. The concave type : when
luxuriant, drooping ; when starved;
more erect : triangular, bright beautiful
green, all the divisions concave
above ; figured at page 60 (the lower
figure) : this is the dumetorum of
Smith and Mackay ; the recurvum of
Bree (concavum of Babington), which
I consider identical, is figured opposite.
In every variety of this species,
the lateral veins are placed alternately
on the midvein, after leaving
which, each sends out an anterior
branch, which hears a nearly circular
mass of thecæ half-way between
its origin and extremity ; all the veins terminate before reaching
the margin: the masses are covered by a loose reniform indusium,
which is attached on one side ; it is soon lost among the
growing thecæ.