32 



BRITISH FERNS- 



ALPINE POLYPODY. 



This plant is the Polypodium alpestre of botanists ; it has 

 also been called variously, Aspidium alpestre, Athyrium 

 alpeslrc, Pseudathyrium alpestre, and Pktffopterit alpestris. 



TIC. 



The Alpine Po- FIG. 5. 



lypody has a short 

 decumbent 





root- 

 stock, producing 

 fronds in tufts 

 from the crown. 

 They are from six 

 inches to three 

 feet or more in 

 height, broadly 

 lance-shaped and 

 attached by com- 

 paratively short 

 stipes, clothed 

 with broadish- 

 pointed mem- 

 branous scales. 

 They are bipin- 

 nate, or some- 

 times subtripin- 

 nate. The lower pinnae are gra- 

 dually shorter, so that the outline 

 is truly lanceolate. The pinnae are 

 linear-lanceolate, taper pointed, 

 spreading at an obtuse angle with 

 the rachis. The pinnules are nu- 

 merous, ovate-oblong, acute, vari- 

 ously pinnatifid, the segments 

 j notched with sharp, coarse teeth ; 

 "* rarely the pinnules are ovate-lance- 

 olate, and in the most vigorous 

 fronds they are so deeply pinnatifid 

 as to become almost tripinnate. 

 The pinnules have a slightly wavy 

 midyein, from which alternately 

 branch the veins which ramify in the lobes ; these veins, in 

 average specimens, are pinnately branched, with a simple 

 venule directed towards each marginal tooth. The son are 

 sometimes produced only on the lowest anterior venule of 



alpestre. 



