632 CLXIV. FILICES. Pteris. 



bling the last, forming tufts on rocks. Plant 2 — 4' high. Fronds lance-linear 

 in outline, on ven' scaly stipes. Leaflets 8 or 10 pairs, subopposite, nearly- 

 round, 2 or 3" in diam., the margins onl}' crenate above, deeply pinnatiSd in 

 the lowest pairs. July. 



4. W. RUFiDULA. Beck. (W. ilvensis and Aspidium rufidulum. Pursh.^ 

 Frond bipinnate ; sef^mcnts of the leaflets hairy, oblong, obtuse, pinnatihd, 



with obtuse, ultimate segments; sm-i at length confluent; 5/?>e and rocAw hairy. 

 —Grows on rocks. Fern 6 — 8' high. Stipe dark brown, densely clothed with 

 woolly hairs. Frond hairy both sides, its leaflets 4—8" long, lower ones dis- 

 tinctly pinnate, upper pinnatifid. July. 



5. WOOD WARD I A. Smith. 



In honor of Thomas J. Woodwanl, a distinguished English botanist. 



Sori oblong, straight, parallel with the ribs on either side of them ; 

 indusium superficial, arched or vaulted, opening inwardly. 



1. W. oNOCLEuiDES. Willd. (W. angustitblia. Smilh.) 



Sterile frondfi pinnatifid; Ifts. lanceolate, repand, slightly serrulate; fertile 

 fronds pinnate, the leaflets entire, linear, acute. — In swamps, not coinmon. 

 Fern about a toot high, growing in tufts. Barren fronds numerous, of a narrow- 

 lanceolate, acuminate outline. Leaflets wdth decurrent or confluent bases. 

 Fertile fronds fewer, with linear segments nearly covered on the back with the 

 fruit in oblong, longitudinal sori i' in length. Aug. 



2. W. ViRGiNiCA. Willd. 



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

 sori in interrupted lines near the midvein of the leaflets and segments. — In low 

 woods and swamps. Frond about 2f high, on a smooth stipe, lanceolate in out- 

 line, and pale 'green. Leaflets alternate, deeply pinnatifid, with numerous, 

 spreading, obtuse and slightlv crenate lobes. Fruit arranged in lines along each 

 side of the midveins, both of the segments and leaflets. July, Aug. 

 6. SCOLOPENDRIUM. Smith. 



Gr. (7Ko\oTr£vS()a, the centipede ; from the number of its roots ? 



Sori linear, transverse, scattered : indusium double, occupying both 

 sides of the sorus, superficial, finally opening lengthwise. 



5. oFFiciNARCM. Willd. (Asplcuium Scolopcudrium. Linn.) HarVs-tonguc. 

 Frond simple, ligulate, acute, entire, cordate at base. — Shady rocks, Chi- 



tenango, N. Y., Sarlwell. Stipe rather short (3—5' long), chafi;y, bearing the 

 frond suberect, 8—15' high, 2—3' wide, bright green, paler beneath. Sori oblique 

 to the midvein, 6—9" in length. Rhizoma large, creeping. July.— This curi- 

 ous fern appears to be confined to the vicinity above mentioned, where it w^as 

 fii'st detected by Pursh, unless the true plant has also been found in Ky. by 

 MMurt. 



7. PTERIS. 

 Gr. irrepov, or irTcpv^, a wing ; from the general resemblance of the frond. 



Sori in a continuous, marginal line : involucre formed of the in- 

 flected margin of the frond, opening inwardly. 



1. P. AauiLlNA. Common Brake. 



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

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

 pastures and waste grounds. Fern 2 — 5f in height, upon a smooth, dark purple, 

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

 visions, which are again subdivided into obtusely pointed, sessile leaflets. The.se 

 are entire above, becoming gradually indented towards the base of each subdi- 

 vision. Sori covered by the folding back of the margins of the segments. 

 July, Aug. 



2. P. ATROPURPUREA. Rock Brake. 



Frond pinnate ; loii-er Ifts. ternate or pinnate, segments lanceolate, obtuse, 

 obliquely trimcate or subcordate at base.— Fern 6—10' high, growing on rocks. 



