Onoclea. CLXIV. FILICES. 033 



Frond twice as long as wide, ol' a f^'iayish hue, the two lower divisions con- 

 eisting of 1 — 3 pairs of leaflets with a larj^e, tt-nninal segment. All the seg- 

 ments lance-linear, distinct, vritli margins cunspicuously revolute. Stipe and 

 rachis dark purple, with dense, paleaceous hairs at base. June — Aug. 



3. P. GRACILIS. Mich.x. (Cheilanthes. i>p/cn<:.) 



F'rmid fi\(;ndcr, lanceolate, sterile ones pinnate, leaflets pinnatiiid, segments 

 broad-ovate, obtuse; frtile bipinnale, leaflets linear-oblong, crenale; stipe dark 

 brown. — A delicate species, growing on rocks. Fern 4 — G' high, smooth and 

 shining in all its parts, Aug. 



8. CHEILANTHES. Swartz. 



Gr. j^ciXoi, lip, av^oi ; from the form of its iiidu.sia. 



Sori roundish, distinct, situated at the margin of the fronds ; in- 

 dusium of mcuiLranous, distinct, inflcxed scales, opening inwardly, 

 sometimes continuous with the frond. 



C. VESTiTA. Swartz. (Nephrodium lano.sum. M?;.) Hairy Cheilanthes. 

 Stipe and rachis hairy; fnmd bipinnate, oblong-ovate in outline, hairy on 



both sides ; kajlcls alternate ; scgvieiUs oblong, alternate, sessile, distinct, crenately 

 pinnatifid, the ultimate segment very entire; sort Anally continuous along the 

 margin. — Rocky banks, Mid. and W. States, frequent. Stipe slender, rigid, 

 2 — 3' long, dark brown. Fronds 3 — G' by 1 — 2'. Leaflets lance-ovate in out- 

 line, G — 12" long. Sori marginal, distinct when yomig, finally crowded. July. 



• 9. ADIANTUM. 



Gr. a, privatiou, diaivu, to moisten; as the rain slides off without wetting it. 



Sori oblong or roundish, marginal ; indusia membranaceous, aris- 

 ing from the reflexcd margins of distinct portions of the frond and 

 opening inwardly. 



A. PED.lTUM. Maidenhair. 



Frond pedate ; division^ 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. DICKS ON I A. L'Her. 



In honor of James Dickson, a distinguished English cr>-ptogamist. 



Sori marginal, roundish, distinct ; indusium double, one superficial, 

 opening outwards, the other marginal and opening inwards. 



D. pii.osR-scuLA. Willd. Finc-haircd Mountain Fern. 



Frond bipinnate; leaflets lanceolate, sessile; segments pinnatifid, decurrent, 

 oblong-ovate, ultimate segments toothed ; sl/pc 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, sol^, 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. Ox\OCLEA. 



Gr. ovos, a kind of vessel, f Xctw, to close ; alluding to the contracted thec«. 



Thecag 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. 



O. sKN'.^iBir,is. Sensitive frrn. 



Sterile frt.nds pinnate; Ichfl-ts lanceolate, acute, laciniate, the upper ones 



