88. PTERIDIOrDES. 305 



1423. Equisetum sylvaticum, Linn. 



Area general. 



South limit hi Devon, Isle of Wight, Kent. 



North limit in Shetland, Orkney, Hebrides. 



Estimate of provinces 18. Estimate of counties 80. 



Latitude 50 — 61. British type of distribution. 



A. A. regions. Inferagrarian — Midarctic zones. 



Descends to the coast level, in the Peninsula. 



Ascends to 900 yards, in East Highlands. 



Range of mean annual temperature 61 — 37. 



Native. Inmidatal, Sylvestral, &c. Less common than 

 E. arvense in England ; but I cannot name a county in 

 which the probability of absence exceeds much that of its 

 presence ; and thus the comital estimate is entered nearly 

 at the highest number. Its less frequency in England, 

 however, is countei-poised by its greater frequency on the 

 northern mountains, where, much above the agrarian re- 

 gion, its branches become almost simi^le, and might cause 

 it to be mistaken for E. arvense or E. umbrosum on a 

 hasty inspection. In England, it seems to grow princi- 

 pally in the shady corners or sides of wet meadows, on 

 banks from which water oozes, and in damp woods, but 

 not in water ; while ujion the Highland mountains it may 

 be seen in the very beds of the streams, and in places 

 almost j)aludal in character. 



VOL. ni, 2 R 



