26 TKANS ACTIONS AND PROCEEDINGS OF THE [Sess. lxv. 



Afjrostis nigra, a probable introduction of late years, appears 

 hardly established as yet. Pastures adjoining sandy shores 

 are continually in a state of alteration in some places, 

 especially in the Hebrides, many acres being rendered useless 

 by having been covered by blown sand, on which little now 

 grows except Fsamma areyiaria. The island of Coll has 

 suffered more in this way than any other of the inner 

 islands, a considerable amount of destruction having taken 

 place in the eighteenth century. M'Culloch, in " The 

 Highlands and Western Isles of Scotland," 1824, gives 

 as the reason why Tiree is not much spoiled in this way is 

 that, owing to the island being so flat, blown sand only 

 forms thin layers, there being no uneven ground to form 

 accumulations. The effect of a small amount of sand, 

 containing as it does so much lime, is to improve the 

 pasture. The occurrence on these sandy pastures of certain 

 plants which are most frequent in other places in limestone 

 districts is interesting. A case in point among flowering 

 plants is Orchis 2^y^c(,midalis, which is rare or absent in 

 inland parts of Britain except on limestone, but which also 

 occurs on sandy shores, due, probably, to the lime from the 

 comminuted shells being sufficient for its growth. Among 

 Hepaticie, I have noticed in such places Scapania aspera, 

 considered otherwise almost purely a limestone species ; 

 >S'. aquiloha, most frequent on limestone ; and Legeuna 

 Mackaii, on rocks coated with blown sand bordering a 

 dune, the last species being also elsewhere most frequently 

 met with on limestone. Elymus arenariiis, a rare native on 

 the coast, has been planted in a few places to assist in 

 preventing further incursions of the sand ; and Fsamma 

 arenaria, a common native species, has been introduced to 

 some parts where it was absent, or in too small quantity 

 previously. As early as the time of William in., an Act 

 was passed by the Scottish Parliament for the preservation 

 of these two species on the coast, so that it was rendered 

 penal for anyone, including the proprietor, to cut them 

 or even to have them in their possession within eight 

 miles of the coast. This is quoted from Sinclair's " Hortus 

 Gramineus Woburnensis." It is doubtful, however, if these 

 laws were often put in force in the West Highlands. Elymus 

 was a rare ))lant on the coast in the eighteenth century. 



