ONOCLEA. CLXIV. FILICES. 633 
Frond. twice as long as wide, of a grayish hue, the two lower divisions con- 
sisting of 1—3 pairs of leaflets with a large, terminal segment. All the seg- 
ments lance-linear, distinct, with margins conspicuously revolute. Stipe and 
rachis dark purple, with dense, paleaceous hairs at base. June—Aug. . 
3. P. eracitis. Michx. (Cheilanthes. Spreng.) 
Frond slender, lanceolate, sterile ones pinnate, leaflets pinnatifid, segments 
broad-ovate, obtuse ; fertile bipinnate, leaflets linear-oblong, crenate; stipe dark 
brown.—A delicate species, growing on rocks. Fern 4—6! high, smooth and 
shining in all its parts. Aug. 
8. CHEILANTHES. Swartz. 
Gr. xevkos, lip; avSos; from the form of its indusia. 
Sori roundish, distinct, situated at the margin of the fronds; in- 
dusium of membranous, distinct, inflexed scales, opening inwardly, 
sometimes continuous with the frond. 
C. vestira. Swartz. (Nephrodium lanosum. Mz.) Hairy Cheilanthes. 
Stipe and rachis hairy ; frond bipinnate, oblong-ovate in outline, hairy on 
both sides ; leaflets alternate ; segments oblong, alternate, sessile, distinct, crenately 
pinnatifid; the ultimate segment very entire; sora finally continuous along the 
margin.—Rocky. banks, Mid. and W. States, frequent. Stipe slender, rigid, 
2—3’ long, dark brown. Fronds 3—6’ by 1—2’. Leaflets lance-ovate in out- 
line, 6—12/’ long. Sori marginal, distinct when young, finally crowded. July. 
9. ADIANTUM. 
G7, a, privation, dtatv, to moisten; as the rain slides off without wetting it. 
Sori oblong or roundish, marginal; indusia membranaceous, aris- 
ing from the reflexed margins of distinct portions of the frond and 
opening inwardly, 
A. PEDATUM. Maidenhair. 
Frond pedate; divisions pinnate; segments oblong-rhomboid, incisely 
lobed on the upper side, obtuse at apex; sori oblong, subulate-——This is, doubt- 
less, the most beautiful of all our ferns, abounding in damp, rocky woods. 
Stipe 8—14’ high, slender, of a deep, glossy purple approaching to a jet-black. 
At top it divides equally into 2 compound branches, each of which gives off, 
at regular intervals, 6—8 simply pinnate leaflets from the outer side, giving the 
whole frond the form of the crescent: Ultimate segments dimidiate, the lower 
margin being bounded by the midvein and the veinlets all unilateral.. July. 
10. DICKSONIA. L’Her. 
In honor of James Dickson, a distinguished English cryptogamist. 
Sori marginal, roundish, distinct ; indusium double, one superficial, 
opening outwards, the other marginal and opening inwards. 
D. prtosiusctLa. Willd. Fine-haired Mountain Fern. 
_ Frond bipinnate ; leaflets lanceolate, sessile; segments pinnatifid, decurrent, 
oblong-ovate, ultimate segments toothed ; stipe a little hairy —A large and deli- 
cate fern, in pastures, roadsides, among rocks and stones. Fronds 2—3f high, 
in tufts, and remarkable for their numerous divisions and subdivisions. Stipe: 
and rachis smooth, with the exception of a few, soft, scattered hairs. Leaflets 
alternate, approximate ; segments deeply divided into 4-toothed, ultimate seg- 
ments. Sori minute, solitary, on the upper margin of the segments. July. 
11. ONOCLEA. 
Gr. ovos, a kind of vessel, «ew, to close; alluding to the contracted thece. 
Thee covering the whole lower surface of the frond ; indusia 
formed of the segments of the frond, whose margins are revolute and 
contracted into the form of a berry, opening, but not expanding. 
QO. sensrBitis. Sensitive fern. 
Sterile fronds pinnate ; leaflets lanceolate, acute, laciniate, the upper ones 
