Not all evergreens are coniferous trees. A
number of ferns are evergreens. The ferns which have starred
as Species of the Week so far,
Christmas fern and walking fern,
have both been evergreen. This week we will look at a rare
evergreen fern that hardly even looks like a fern: wall rue.
The common name comes from the fact that the leaves look the leaves
of the bitter herb known as rue, and it likes to grow in crevices in
limestone boulders and cliffs. It is a small delicate fern,
with two to four pairs of leaves divided into somewhat triangular
leaflets with scalloped or tattered-looking edges. To me, it
looks like parsley.
Wall rue likes shady boulders in limestone regions
from southern Ontario to Quebec south through New England and the
Appalachian Mountains. It is also found in isolated
populations along the shores of the Great Lakes and in Missouri and
Arkansas. It is also native to Europe and eastern Asia.
Despite this wide range, it is not common, according to Broughton
Cobb, author of the Peterson Field Guide to the Ferns.
It appears to be quite rare in Wildwood, being found, as far as I
know, on only two boulders on the eastern slopes of the Park.
It is not hard to find, if you look for improbable parsley plants.
Should you find it, please do it no harm. Should you find more
plants than two, please let me know of them.
Ferns of the genus Asplenium are known as
spleenworts because some members were long thought to be useful in
the treatment of diseases of the spleen. As far as I know,
this is a mistaken belief. The genus name, not surprisingly,
comes from the Greek word for spleen. The species name
ruta-muraria is simply Latin for "wall rue."