463 ADIANTUM. 



1. W. onocleoi'des. Willd. W. angustifolia. Umil/t. 

 Sterile fronds pinnatiM; leaflets lanceolate, repand, slightly serrulate; 



fertile fronds pinnate, the leaflets entire, linear, acute. In swamps; not 

 common. Fern about a foot high, growing in tut\s. Barren fronds numerous, 

 of a narrow-lanceolate, acuminate outline. Leaflets with decurrent or conflu- 

 ent bases. Fertile fronds fewer, with linear segments nearly covered on the 

 back with the fruit in oblong, longitudinal sori \ inch in length. Aug. 



2. W. Virgi'nica. 



Frond pinnate, very smooth, the leaflets pinnatifid, lanceolate, sessile; sori 

 in interrupted lines near the midrib of the leaflets and segments. In low 

 woods and swamps. Frond about 2 feet high, on a smooth stipe, lanceolate 

 in outline, and pale green. Leaflets alternate, deeply pinnatifid, with 

 numerous, spreading, obtuse and slightly crenate lobes. Fruit arranged in 

 lines along each side of the midribs both of the segments and leaflets. Jl. Aug. 



6. PTERIS. 

 Sori in a conlinuous, marginal line; involucre formed of 

 the inflected margin of the frond, opening inwardly. 



1. P. aq,uili'na. Common Brake. 



Frond 3-parted ; branches bipinnate ; leaflets linear-lanceolate, lower ones 

 pinnatifid, upper ones entire ; segments oblong, obtuse. Common in woods, 

 pastures and waste grounds. Fern 2 — 5 feet in hight, upon a smooth, dark 

 purple, erect stipe. Frond broad-triangular in outline, consisting of 3 primary 

 divisions, which are again subdivided into obtusely pointed, sessile leaflets. 

 These are entire above, becoming gradually indented towards tlie base of each 

 subdivision. Sori covered by the "folding back of the margins of the seg- 

 ments. July. Aug. 



2. P. ATRopuRPo'REA. Roclc Brolie. 



Frond pinnate ; lower haflets ternate or pinnate, segments lanceolate, obtuse, 

 obliquely truncate, or subcordate at base. Fern 6 — 10 inches higli, growing 

 on rocks. Frond twice as long as wide, of a grayish hue, the two lower divis- 

 ions consisting of 1 — 3 pairs of leaflets with a large terminal segment. All 

 the segments lance-linear, distinct, with margins conspicuously revolute. 

 Slipe and rachis dark purple, with dense, paleaceous hairs at base. Jn. — Aug. 



3. P. gba'cilis. ^fz. Cheilanthes. Sjpreng. 

 Frond slender, lanceolate, sterile ones pinnate, leaflets pinnatifid, segments 



broad-ovate, obtuse; /firti/c bipinnate, leaflets linear-oblong, crenate ; stipe 

 dark-brown. A delicate species, growing on rocks. Fern 4 — G inches high, 

 smooth and shining in all its parts, Aug. 



7. ADIA'NTUM. 

 Sori oblong or roundish, marginal ; indusia membranace- 

 ous, arising from the reflexed margin of distinct portions of 

 the frond and opening inwardly. 



A. peda'tusi. Maidenhair. 



F/o?»Z pedate ; divisions pinnate; segments oblong-rhomboid, incisely lobed 

 on the upper side, obtuse at apex; sor^ oblong, sublunate. This is, doubtless, 

 the most beautiful of all our ferns, abounding in damp, rocky woods. Stipe 

 8—14 inches high, slender, of a deep, glossy purple approaching to a jet black. 



