H a b . — Clefts of rocks, in canons and on mountains, from the
Rio Grande to Arizona, and perhaps extending into Mexico. It is
C h a r l e s W r ig h t ’s N o. 821, collected beuveen Western Texas and New
Mexico. It has been sent from New Mexico also by Dr. B ig e low ,
Mr. SciioiT and Dr. S e g u in , and was found near Camp Bowie, in Arizona,
by Professor R o th ro c k and Mrs. vS u m x e r . It has recently been
collected on the journey from San Luis Potosi, in Mexico, to San Antonio,
Texas, by Dr. P a r r y (No. 992).
D e s c r i p t i o n : — This fern has, like most of the ferns
which grow in the clefts of rocks, a creeping and rather short
root-stock, well covered with scales. The scales are two or
three lines long, lanceolate, and appressed to the root-stock.
They consist of a very broad and rigid, dark-brown and shining
midnerve, which has a narrow border of more delicate
and paler cells on each side. The stalks are clustered at the
end of the root-stock, and are dark-brown, shining, wiry and
nearly erect. Near the base they bear a few scales, which
are shorter and broader than those of the root-stock, and have
a narrow midnerve. The section discloses a single roundish
fibro-vascular bundle, having the ducts which it contains arranged
in a somewhat lunate form.
The fronds have an outline between that of. a pentagon
and that of a five-pointed star. They consist of a middle
portion of a rhomboid-ovate form, supported on a short but
narrowly winged stalk, and two lateral divisions, which are
sessile. The middle part is pinnatifid nearly to the midrib
into a few oblong-lanceolate crenate and often sub-falcate
lobes; while the lateral divisions have each on the lower side
a very large pinnatifid basal segment, the rest of the segments
being similar to those of the middle division, though
a trifle smaller. The whole frond is thus five-rayed, the middle
ray largest, and the two lower rays smallest. The upper
surface of the frond is smooth, and of a dull, though rather
dark, shade of green. The under-surface, with the exception
of the midribs, is covered with a waxy powder, like that of
Notholæna candida and Gymnogramme triangularis, and probably
equally variable in color. The specimens first collected
by Mr. Wright have the powder almost white; those sent
afterwards from New Mexico have it of a pale sulphur-yellow,
and those just received from Dr. Parry have it of a deep
yellow, inclining to orange.
The veins are free and forking. The sporangia are
borne on the ends of the veins, just within the margin,
which is slightly recurved, but not so as to form a true involucre.
The spores are slightly trigonous, and have the usual
three radiating vittæ of such spores.
This fern was considered “ probably a distinct species”
by Sir W. J . Plooker, though at the same time he made of
it a variety of N. candida. I have thought, at times, that I
could identify it with N. cretacea, of Liebmann, or with
Cheilanthes Borsigiana, of Mettenius; but both of these seem
to be forms of N. candida, from all forms of which species
this one can be distinguished by the lowest segments of the
middle division being smaller than the next superior segments.