87. FILICES. 289 



U^Jt.-ft^. 1408. Hymenophtllum WiLSONi, JfooA;. 



Area 1 * * * 5 6 7 * 9 10 * 12 13 14 15 16 17 18. 



Soutli limit in Cornwall, Devon. 



North limit in Shetland, Orkney, Hebrides. 



Estimate of provinces 13. Estimate of counties 40. 



Latitude 60 — 61. Highland tyi^e of distribution. 



A. A. regions. Midagrarian — Midarctic zones. 



Descends to the coast level, in West Highlands. 



Ascends to 950 yards, in Hebrides (Balf. & Bab.). 



Range of mean annual temperature 49 — 37. 



Native. Rupestral. Ascertained in 26 counties, and 

 doubtless reported for others under name of H. tun- 

 bridgense. I have seen this species in North Wales, at 

 heights ranging from 650 to 2000 feet ; and in the West 

 Highlands, from the level of Loch Lomond, not much 

 above the sea, to perhaps 1500 feet on the acclivities of 

 Ben Nevis. By Balfour and Babington it was observed 

 on the summit of Langa, in Harris (Cat. Heb. p. 23), and 

 they give fair grounds for estimating that hill at upwards 

 of 2700 feet (Cat. Heb. p. 8), although its altitude has not 

 been ascertained by admeasurement. As this fern grows 

 on Carn Brea in Cornwall, a hill of about 700 feet, it there 

 descends nearly or quite within the mferagrarian zone, 

 and may be more clearly within the same zone elsewhere. 

 According to modern records, this species would seem 

 to be more boreal and alpine than the other ; and though 

 still preserving something of the western tendency, its 

 tji^e is on the whole nearer to the Highland than to the 

 Atlantic. It rather descends than ascends the western 

 side of Britain. Occurs in Faroe, and locally in Norway. 

 " In Ireland this fern is much more common than in 



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