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7 0 FERNS OF NORTH AMERICA.
about fifty miles above its confluence,” P u r sh , N u t t a l l . “ Dry calcareous
rocks, on their perpendicular faces, and chiefly where sheltered by the overhanging
projections ; rather common in Middle and Southern Kansas,”
E . H a l l , P a r r y . Texas, Herb. D u r a n d . New Mexico and Arizona, P a r r y ,
R othrock, Mrs. S u m n e r .
D e s c r i p t io n .— This little fern is in many respects like the
species last described. It has the same dense white ceraceous or
farinose coating on the under surface of the pinnules : the frond
is decompound, the pinnules equally minute, and very similar in
shape. The stalks and rachises are perhaps more nearly black,
and have a somewhat higher polish. The most evident distinctions
are, however, (i) the smaller size and greater delicacy of the
present species, and (2) the fact that in this fern the pinnæ and
pinnules of every degree are opposite in pairs, or nearly opposite.
The ultimate pinnules* are more generally entire than in the
larger species, and have a stronger tendency to become revolute,
or strongly rolled under from both margins.
The specimens from Missouri and Kansas are very delicate,
the whole plant not more than four inches high, and the nearly
black branchlets almost as fine as horse-hair. The specimens
from Arizona collected by Dr. Parry are equally delicate ; but
those from the Sonoita Valley in Arizona, collected by Dr. Roth-
rock, and from Camp Bowie in South-western New Mexico, collected
by Mrs. Sumner, are considerably larger, and with heavier
stalks and rachises.
In the “ Species Filicum” Sir William Hooker intimated
that it is difficult to see how this plant is to be satisfactorily dis-
FERNS OF NORTH AMERICA. 7 1
tinguished from N. nivea, a native of Tropical America; but the
latter species is much coarser in every way, has longer and less
compound fronds, far heavier stalks and rachises, and larger ultimate
pinnules.
Plate IX., Fig. 2 .— Notholoeiza dealbata, drawn from Mrs. Sumner’s
specimen, showing the under surface only.
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