BOTANICAL FEATUEES OF IRELAND xxxv 



Lough Neagh. About the year 1850 the level of the lake was 

 permanently lowered by some ten feet. Since that date Rhamjms 

 catharticus, R. Frangula, Lathyrus palustris, Slum latifoliuin, Carex 

 Buxbaumii, C. elongata, C. filiformis, C. jxiliiclosa, LastreciThelypteris, 

 Pilulana glohulifera, Tolypella nidifica (?), many of which were, in 

 the north-east, confined to Lough Neagh, have either entirely dis- 

 appeared, or have become extremely rare. The gravel-beaches 

 furnish examples of the disappearance of native plants owing to 

 the removal of shingle and the building of sea-waUs and fascines. 

 Matthiola sinuata, Cramhe maritima, Calystegia Soldanella, Mertensia 

 maritima, and others are decreasing on this account. 



Lastly, certain plants — very few, fortunately — are becoming 

 extinct through the direct act of man. The Yew has been almost 

 exterminated in certain districts — for smelting purposes at Killarney, 

 for religious festivals in the north-east ; the beautiful Killarney 

 Fern has been ruthlessly destroyed for mere gain wherever found '; 

 the lovely Maidenhair of the Aran Isles is Uke to follow ; and 

 about the larger towns our favourite wild-flowers and ferns are 

 vanishing rapidly. 



To leave this painful subject, the flora has, on the other hand, 

 been considerably enriched by the operations of man — though many 

 of these acquisitions, the husbandman and gardener would willingly 

 do without. It is in the deliberate or accidental introduction of a 

 large number of species that the influence of man upon the flora is 

 chiefly seen. Such plants may be grouped under several heads. 



The majority of our introduced species are plants of cultivated 

 land. These vary in standing from mere fleeting waifs (casuals) 

 to species which are now well established throughout the country, 

 though beheved to have been originally introduced (colonists). The 

 Poppies, Fumitories, Corn-salads, furnish good examples of the 

 latter group, being probably of early accidental introduction ; Crepis 

 biennis, C. taraxaclfoLia, Orohanche minor, Veronica peregrina are 

 examples of more recent arrivals of the same kind. Other plants 

 have been dehberately introduced, and have escaped from the 

 bounds of cultivation ; such as Petasites fraqrans, Mimidus guttatus, 

 and Acorus Calamics. The head-quarters of the group is in tilled 

 fields and garden-plots, and while some of the plants have effected 



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