THE SMOOTH THREE-BRANCHED POLYPODY. 
THE SMOOTH THREE-BRANCHED POLYPODY, 
or OAK FERN. 
POLYPODIUM DRYOPTERIS. 
P. fronds pentangular-deltoid, ternate, smooth, membranaceous ; 
branches pinnate; pinne deeply pinnatifid (sometimes pinnate at 
the base); lobules or pinnules oblong, obtuse, crenate or crenately 
lobate; stipes glabrous. [Plate XIJ 
POLYPODIUM DRYOPTERIS, Linneus, Sp. Plant. 1555. Bolton, Fil. Brit. 52, t. 28. 
Smith, Fl. Brit. 1116 ; Id., Eng. Bot. ix. t. 616 ; Id., Eng. Fl. 2 ed. iv. 269. 
Hudson, Fl. Ang. 460. Deakin, Florigr. Brit. iv. 42, fig. 1581. Hooker & 
Arnott, Brit. Fl. 7 ed. 582. Babington, Man. Brit. Bot. 4 ed. 420. Sow- 
erby, Ferns of Gt. Brit. 11, t. 3. Moore, Handb. Brit. Ferns, 3 ed. 64; Id., 
Ferns of Gt. Brit. and Ireland, Nature Printed, t. 5. Mackay, Fl. Hib. 
338. Bentham, Handb. Brit. Fl. 626. Lowe, Nat. Hist. Ferns, i. t. 27. 
Schkuhr, Krypt. Gew. 19, t. 25. Willdenow, Sp. Plant. v. 209. Sprengel, 
Syst. Veg. iv. 60. Presl, Tent. Pier. 180. Fries, Sum. Veg. 82. Koch, Synops. 
2 ed. 974. Gray, Bot. North. U. States, 590. Flora Danica, tt. 759, 1943. 
Sturm, Deutschl. Fl. (Farrn.) t. 7. 
POLYPODIUM DRYOPTERIS, a. GENUINUM, Ledebour, Fl. Ross. iv. 509. 
POLYPODIUM PULCHELLUM, Salisbury, Prod. 403. 
POLYSTICHUM DRYOPTERIS, Roth, Pl. Germ. id. 80. 
LASTREA DRYOPTERIS, Bory, Dict. Class. d Hist. Nat. ix. 233. Newman, Nat. 
Alm. 1844, 15; Id., Brit. Ferns, 2 ed. 13. 
PHEGOPTERIS DRYOPTERIS, Fee, Gen. Fil. 243. J. Smith, Cat. Cult. Ferns, 17. 
GYMNOCARPIUM DRYOPTERIS, Newman, Phytol. iv. 371; Id., 1851, Appendix, 
xxiv. ; Zd., Hist. Brit. Ferns, 3 ed. 57. 
Caudex creeping extensively, branched, tough, slender, about the 
thickness of a straw, dark-brown, almost black, the younger por- 
tions scaly. Scales lanceolate, like those of the stipes, pale semi- 
transparent brown. Fibres dark-brown, branched, clothed with fine 
pubescence. 
Vernation eireinate; the lateral or lower pair of branches rolled 
up separately from the remaining central portion, so that the young 
fronds resemble, as Mr. Newman expresses it, three little balls set 
on slender wires at the top of the stipes. 
Stipes very much longer than the fronds, frequently twice or 
thrice their length, erect, slender, brittle, tinged with purple, and 
furnished near the base with a few scattered pale-brown lanceolate 

