1913-14.] BOTANICAL SOCIETY OF EDINBURGH 265 



ponticum, Linn., grows everywhere with great vigour. 

 and seeds abundantly, competing successfully against the 

 sturdiest of native plants. 



Under the shade of these trees, and on the steep rocky 

 banks which form the bed of the Ardyne Burn, are to be 

 found some characteristic woodland associations of three 

 or four different types, but all merging imperceptibly into 

 one another. These may be roughly summarised under 

 the following heads : — 



1. Cryptogamic Association. 



2. Mercurialis dominant. 



3. Luzula dominant. 



■i. Vacciniuin-Teucrium Association. 



1. Cryptogamic Association. — From the rocks in the 

 bed of the burn to the dripping banks and rocky clefts 

 along the sides of its course, there is a series of situations 

 forming a congenial home for the moisture- and shade- 

 loving ferns, mosses, and liverworts. Among the ferns 

 Nephrodiwm Filix-mas, Rich.; X dilatatum, Desv.; and 

 Atkyriv/m FiUx-foemina, Bernh., are the commonest 

 species, and are distributed in almost all situations. 

 Polypodium uvlgare, Linn., is common as an epiphyte 

 on tree-trunks; Asphrnium trichomanes, Linn., is a com- 

 mon occupant of crevices in the rocks, while Lomo.rio 

 Spicant, Desv., is frequent in drier and more open 

 situations. 



Among the mosses, where so many are common, it is 

 difficult to single out a few, but three or four species at 

 least cannot fail to be familiar to the wanderer of these 

 woods, even though they be not known to him by name. 

 Milium liornum, Linn., is present under almost every tree, 

 and forms extensive carpets under beech trees, where 

 frequently few or no competitors dispute its entire posses- 

 sion of deeply shaded banks. Polytricltum commune, 

 Linn., is conspicuous in its size and frequency, as well as 

 in its tall erect habit. Thuidiv/m tamariscinv/m, B. et S., 

 another common species, is remarkable for the beauty of 

 its fern-like branching form, while thick soft tufts of 

 Dicranum scoparium, Hedw., and D. majus, Turn., shine 

 out in winter with a rich emerald green, unrivalled in its 

 depth and brilliancy. 



