87. FiLiCES. 249 



fern seems particularly to prevail on calcareous rocks and 

 on walls, though not quite restricted to such situations. 

 Mr. E. W. Smith (Phytol. iv. 276) finds it growing as an 

 epiphyte in the vicinity of Winchester ; but the tree on 

 which it occurs there is stated to overhang a deep chalk 

 lane. 



1873. WOODSIA ILVENSIS, Br. 



Area ******7** [10] 11 [12] 13 * 15. 



South limit in Caernarvon, Durham. [Westmoreland ?] 



North limit in Forfar, Dumfries. [Perth ? Peebles ?] 



Estimate of provinces 5. Estimate of counties 6. 



Latitude 53 — 57. Highland type of distribution. 



Arctic region. Inferarctic zone. 



Descends to 650 yards, less or more. 



Ascends to 700 yards, more or less. 



Range of mean annual temperature (about) 41 — 40. 



Native. Rupestral. A very scarce fern, hitherto as- 

 certained only in the four counties indicated above, and 

 reported from an equal number of others, uncertainly or 

 erroneousl3^ In the first edition of the ' Analysis of 

 British Ferns', by Mr. Francis, a locality is thus indi- 

 cated ; " Near Richmond, Yorkshire, Mr. J. Wood ". This 

 was an error of compilation, and it is excluded from the 

 second edition. But it re-appears in the Yorkshire Flora, 

 by Mr. Baines, along with two other localities (or two de- 

 scriptions of one single locality) which are probably in 

 Durham, and thus should have had no place in a Yorkshire 

 Flora. The county, however, is not an unlikely one for 

 the plant. Again, Mr. Sylvanus Thompson has recorded 

 (Phytologist i. 331) that a single frond of Woodsia ilvensis 

 was gathered by his father, from Crosby Ravensworth 



VOL. III. 2 K 



