EAY S WOODSIA. 



genus Acrostichum : Withering, Sowerby, Willdenow, Sprengel, 

 Schkuhr, Wahlenberg, and Presl, in the genus Pol^^podium : 

 Lamarck and DecandoUe in the genus Ceterach : Smith, Hook- 

 er, Sadler, and Babington, in the genus Woodsia, instituted by 

 Dr. Robert Brown purposely to receive them : my own judg- 

 ment, if deduced from an inspection of the plants only, and 

 without reference to books, would lead me to unite the genera 

 Woodsia and Cystopteris. The description of this genus was 

 published in the eleventh volume of the Linnean ' Transac- 

 tions,' and its distinguishing character consists in the peculiar 

 structure of the involucre, which is inserted under the cluster 

 of capsules, the attachment of which it surrounds, while its 

 margin, as in the linear involucre of Pteris, already described, 

 is split into a number of articulated capillary segments, which 

 intermingle with the capsules and partially conceal them. 



The geographical range of Woodsia Ilvensis is somewhat 

 extensive. It is of common occurrence in Norway, Lapland, 

 Sweden, and Northern Eussia : it occurs, but less frequently, 

 in Denmark, Germany, Hungary, France, Italy, and Spain, 

 and extends throughout Siberia into Kamtchatka : it is also 

 recorded as a native of North America. But in the whole of 

 these instances I can only speak as to the record of the name ; 

 I will not venture to assert that the British plant is thus 

 widely distributed. 



In Britain this is one of the rarest of our ferns : it roots in 

 the fissures of rocks in the most bleak and exposed mountain- 

 ous regions : it has hitherto occurred to botanists in two coun- 

 ties in England, one in Wales, and probably three or four in 

 Scotland : but this excessive rarity is perhaps partly ideal, as 

 every year seems to extend the number of ascertained localities. 



FoEFABSHiEE. — I am indebted to Dr. GreviUe for a specimen from the 

 Clova mountains ; and the very fine specimen represented at fig. c (page 

 71), was gathered in August, 1836, in Glen Fiadh, by Mr. WUson, who 

 most obligingly favoured me with the drawing, of which that figure is afac 

 simiU copy. Mr. Tatham, of Settle, the Messrs. Backhouse, Mr. West- 

 combe, and several other botanists, have observed it in the same glen. 



