Ридте У 
THE SMOOTH THREE-BRANCHED POLYPODY, 
or OAK FERN (Рогурорим Drvorreris). 
POLYPODIUM, Linens, 
Clusters of Spore-cases civeular, without covers, growing from the hack of the veins, 
terminal, or nearly so. Veins disunited at their extremities, their branches 
venudes) simple, forked or rarely pinnate 
P. Davorremis; fronds pentangular-deltoid, ternate, smooth, membranaceous 
pinnate ; pinnæ deeply pinnatifid (sometimes pinnate at the base); lo 
pinnules) oblong, obtuse, erenate or pinnatifid-erenate ; stipes glabrous. 
EXPLANATION OF THE PLATE, 
Rhizome exe 
ing extensively, branched, tough, slender, about the thickness of a straw, dark 
brown—almost black, the younger portions sealy. Seat 
les like those of the stipes, pale semi 
transparent brown, lanecol 
Fibres dark-brown, branched, apparently without pubescence 
Stipes very much lo 
than the fronds, frequently twice or thrice their length, erect, slender 
brittle, tinged with purp 
ind furnished near the base with a few scattered pale-brown lanceolate 
deciduous scales, otherwise smooth and glabrous; lateral on the rhizome, and somewhat distant 
Ra 
his quite smooth ; that of the central branch deflexed, of the lateral 
‚ches spreading. 
Vernation ereinate ; the lateral and lower pair of branches rolled up separately from the remaining 
central portion, so that the young fronds resemble, as Mr. Newman expre 
wires at the top of the stipes 
Fronds from four to twelve or fourteen in 
in height, including the stipes, the leafy portion 
averaging four or five inches ; adherent to the rhizome, delicately membranaceous, bright green, quite 
smooth; in form deltoidly-pentangular, the pentagon being described by the points of the three 
