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2 0 4 F E R N S OF NORTH AM ER ICA .
Plalyioma andromedoefolium, J. S m ith in Hooker’s Lond. Jour. Bot., iv.,
p. i6o. — B r a c k e n r id g e , Filices of U. S. Expl. Exp., p. 94.
Crypteris divaricata and C. pubescens, N u t t a l l , in Herb. Hook.
Pellæa myrtillifolia. M e t t e n iu s ; K u h n , in Linnæa, xxvi., p. 85 (the
Chilian plant).
H a b . — Exposed rocks in ravines and canons, sometimes growing
on hillsides; California, mostly in the Coast Ranges, possibly extending
to Arizona and North-western Mexico. I know of no specimens collected
north of California, those sent by Capt. Wallace from “ Frazer’s
R iv e r ” being probably Californian. The fern re-appears in Chili and
in South Africa.
D e s c r i p t i o n . —-The root-stock is a few inches long, fleshy
when living, but rigid when dried, round, and covered with rusty-
brown somewhat crisped narrow chaffy scales. The stalks are
scattered along the root-stock, erect, wiry, terete, light-reddish-
brown, with a delicate bloom when fresh, duller when dry, chaffy
only at the very base. The fibro-vascular bundle is very peculiar,
and deserves special microscopic study. It is central,
roundish-triangular, with slightly impressed sides, the interior
part containing a three-armed projection from the middle of
one of the sides.
The frond is broadly triangular-ovate in outline, from a
few inches to over a foot in length, and usually thrice pinnate,
but sometimes four times pinnate at the base. The rachis is
usually terete like the stalk, but is sometimes slightly flattened
or even obscurely channelled on the upper side. Though commonly
straight, it becomes a little flexuous when the pinnæ are
F ERNS OF NORTH AMERICA. 2 0 5
alternate. The lower pinnæ are distant, ovate-lanceolate, short-
stalked, and commonly bi-pinnate; the upper ones gradually
shorter and simpler, and several of the uppermost reduced to
single leaflets. The leaflets, or ultimate pinnules, are dull-
green above, paler and somewhat glaucous beneath, sub-coriaceous,
oval or ovate, and usually slightly cordate at the base,
and faintly notched at the rounded apex. Their length is from
two to five or even eight lines. In the sterile fronds they are
perfectly flat, and have a faint harrow whitish border ; but in the
fertile fronds, which are much commoner, the margin is rolled
under so as to cover the sporangia, and the whitish border
becomes more distinct, and like an involucre. Very often the
pinnules have their edges rolled under clear to the midvein,
so that they are pod-like, and the fruit is completely hidden.
In each pinnule there is a central vein, and several widely
divergent veins on each side. These veins are forked near
the midvein, and their branches often forked again. The
veinlets are straight, and, when the pinnules are rolled up,
often appear as minute striations on the upper surface.
The sporangia are seated on the tips of the veinlets, and
form a band along the sides of the pinnules just beneath the
revolute margins. The spores are trihedric-globose, and appear
to be roughened with irregular reticulating ridges.
While the frond, with its rachis and branches, is usually
smooth, and even colored with a faint plum-like bloom, it is
sometimes slightly pubescent, and is then the var. pubescens of
Baker (Syn. F il, 1. c.), the Crypleris pubescens of Nuttall.
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