THE LIMESTONE POLYPODY. 87 



WHERE FOUND. In England, in the counties of 

 Chester, Cornwall, Cumberland, Derby, Devon, Durham, 

 Gloucester, Hereford, Lancaster, Lincoln, Monmouth, 

 Northumberland, Oxford, Salop, Somerset, Stafford, 

 Sussex, Warwick, Westmoreland, Worcester, and York. 

 In Wales, in the counties of Anglesea, Brecknock, 

 Caernarvon, Cardigan, Denbigh, Flint, Glamorgan, 

 Merioneth, Montgomery, Pembroke, and Radnor. In 

 Scotland, in the counties of Aberdeen, Argyle, Ayr, 

 Banff, Berwick, Caithness, Clackmannan, Dumbarton, 

 Dumfries, Edinburgh, Elgin, Fife, Forfar, Inverness, 

 Kincardine, Kinross, Kirkcudbright, Lanark, Linlithgow, 

 Nairn, Peebles, Perth, Renfrew, Ross, Roxburgh, Sel- 

 kirk, Stirling, and Sutherland. In the isles of Arran and 

 Mull, and in Shetland. In Ireland, only in the counties 

 of Antrim, Down, Galway, and Kerry. It ' is found 

 growing up to and at elevations of two thousand seven 

 hundred feet above the sea-level. 



XX. THE LIMESTONE POLYPODY. 



Polypodium calcareum. 

 (Plate IX., Fig. 2, page 65.) 



LENGTH OF FROND. Eight to eighteen inches. 



GENERAL DESCRIPTION. Roots black, numerous 

 fibrous. Rootstock, a rhizoma branched, slender, black, 

 extensively creeping. Fronds abundant, triangular, 

 bluish-green, produced from numerous points of the 

 upper sides of the rhizomas ; less fragile than those of 

 Polypodium dryopteris ; stipes of varying lengths, 

 generally longer than the leafy part, pale green, bipin- 

 nate, and, in large and luxuriant specimens, tripinnate ; 



