Plate V. 



THE SMOOTH THREE-BRANCHED POLYPODY, 

 or OAK FERN (Poiypodiom Duyopteris). 



POLY PODIUM, Linnaus. 



Clutters of Spore-cwes circular, without covers, growing from the bock of the veins, 

 terminal or nearly so. Vriw disunited at their extremities, their branches 

 {venules} simple, forked or rarely pinnate. 



P. Dhyoptbris; fronds pentangular- deltoid, tomato smooth, membranaceous; branches 

 pinnate; pinna* deeply pinnatifid (sometimes pinnate at the base); lobules (or 

 pinnules) oblong, obtuse, ercnatc or pinnatiiid-crcnato ; stipes glabrous. 



FdLYfftllttl D«ohwi», / ( « tf «»,5^rtW^r« 1 lW5. Smith, Fhr* Brit*****, \M - t fiwti*. /Mm 

 Ij t.isn.i; fflvtiriJPhr^flff^ir.aft Ihtt^PJ*** Brit*****, &,%.*<. Jk^MtrifrqM* &&*»**+ 

 h 43, liotfar <W ,rY*w/, BrttUm Vhrm, ZC7. JUhijf^^ M***rf ,/ ItrtiM JMny, kKX oWriy, Aw, 

 II. tS. MrtrtJtwJb^tfUeUUKFtn^* <&..&&. .Vvi f y ( /7^//iW ll ;« 1 :uv &*****, &ntoomfa£ 

 0*rM*f, I0 t U '23. Htildfrnm. ^» JV*iifor»t v. 20&. tf/mp J, *>/»» IWotAW, ir, 00, /VeW 



Potv>T<curM DftYOmUf, ifcrt^ >7gim Ger****t<m, in. SO. 



himu IPtTOmftU, JfiNMj Xattntuf* J/*wwr, 1SH, lfl; JtoAat JVrw, 2 cd_, 13. 

 PHKOomiti Dhoi-ieiii*, JVV, Owai Mu, £13. 



EXPLANATION OF THE PLATE. 

 Putk V.— rortrowm Duonmwi from AmbWie^ We«t»orctaiiL Jf7*t A /frewr. 



11AR1TA IV-Thi* rVrn, though not i roinnoa r>umt,i* rather whirl; ili»j«nr,l in i!rcnt Britain, It U ret? rare in Ireland 

 the county of Antrim being the only certain fc*bi(at recorded. **rem the northern and north.werterii Mand. El 

 appear* to bo aWnlt it* north litnit Ofourrinf fn Suthrrlnuhbirv. Hcnc* it intend* Mtbwuil*, through the 

 J*m-kuid» of Scotland and tho north of Kit-bnd. bit* South Wolc* unit the centre of England, Avoiding tho ewlcm 

 ml*, and occurring n{ciin in Jtaoailiu* Dear tho extreme »utW«t + Tor authentic rpodmtm from tiui Inter 

 count? wo ore indebted to the Rot. J, Mill Chafer. A* regard* deration ii extend, froa near the « Ictcl Id 

 DtftOtMhH to a height of about 2700 fort in the Wmt Jlitfdaadm It oxan principal!; in wild ^d mounnwnou* 

 rock;dudrieta,in the neighbourhood of »»trrfalK»d to tlw^ 

 ilL*trVt* ilotig with P. Robertitnem. 



O£0GHAI-IIICAL DIOTAIBOTID»,-no distribution of tli Fcro So Europe WgrKnL ft * found at North Capo the 

 eUremc northern point, fa lapland Sweden and Kuaui, in German; Hangup and Croatia, in Qrurt BriUu, Fn***, 

 SwiUcrUnd, Italy. Spata and Oihmltnr. Siberia $M K^U^hxlln, ui Ada, abo jivU it; vul it If records from 

 AiHcm. hi tho New World it U m wldelr di»perped w in Bwoftfr, occurring in Ubrador and OreenUnd on the north* 

 MUmtUoi At Sitka, and nbout A*aUehka IIa>\the Rorlj Mountiuivond the Colombia Hirer, on the north-voatrni 

 »do (//*. /roohv), aa veil ii throu^hoot tho United Stale*, and in Newfoundland <//A, ,V«. ^rtf t ) 



tlhizmne creeping extensively, branched, tough, slender, about the thickness of a straw, dark- 

 brown— almost black, the younger portions scaly. Scales like those of tho stipes, pale semi- 

 transparent brown, lanceolate Fibre* dark-brown, branched, apparently without pubescence. 



Stapes very much longer than the fronds, frequently twice or thrice their length, erect, slender, 

 brittle, tinged with pnrple, and furnished near the base with a few scattered pale-brown lanceolate 

 deciduous scales, otherwise smooth and glabrous; lateral on the rhizome, and somewhat distant. 

 Radii* rpiite smooth ; that of the central branch detlexcd, of the lateral brunches spreading. 



Vernation circinato ; the lateral and lower |mir of branches rolled up sejNiratcly from the remaining 

 central portion, SO that the young fronds resemble, as Mr. Newman expresses it, three little ball* on 

 wires at the top of the stipes. 



Fronds from four to twelve Or fourteen inches in height, including the stipes, tho leafy portion 

 averaging four or live inches ; adherent to tho rhizome, delicately membranaceous, bright green, quite 

 smooth ; in form ddtoidly-pontangular, the ijcutagon being described by the points of the three 



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