1909- Adams. — Distitigjcishing Plants in Irelaiid. 129 



6. What is the date of its first being observed iii Ireland ? Has 

 it an ancient Irish name ? — In the Cybele Hibcrnica and Colgan's 

 Flor% of the Co. Dublin will he found the dates of the tirst 

 records of some Irish species. A plant such as Canadian 

 Water-Th3'nie, which is now so common over the country, 

 would surely have been mentioned by some old writer if it 

 had been in Ireland for centuries. Its first recorded appear- 

 ance was about the year 1836 in Co. Down, the presump- 

 tion being that it was introduced. 



But little stress can be laid on the plants having an Irish 

 name if this is a modern one — as in ihe case of Tobacco and 

 Potato. If, on ihe other hand, the name occurs in some old 

 record or has given rise to a place-name, there is a strong pro- 

 bability of the species in that case being native 



7. Has the species ever bee7i cultivated in field or garden for 

 use or ornament ? — The fact that plants like Hop and Vervain 

 were formerly cultivated vitiates to a large extent their claim 

 to be considered native, even though they may occur in what 

 looks like perfectly wild surroundings. 



A wild plant, on the other hand, may sometimes, on account 

 of its beauty, be cultivated in gardens, as in the case of Fox- 

 glove and Welsh Poppy. 



8. Is the species ever introduced at the present ti^ne accidentally 

 in conseq2ie7ice of trading operations with foreig^i countries ? — The 

 various methods of introduction have already been referred to. 

 Thlaspi arvense, Linn., and Lych^iis Githago, Scop., are both 

 being introduced at present among foreign seeds. There is 

 therefore a presumption that they were originally brought to 

 this country in the same way. 



9. Has the species extended its range very considerably within 

 recent years ? — Some introduced species, finding the Irish 

 climate well adapted to their requirements, have extended 

 their range very markedly in a few years. Canadian Water- 

 Thyme was an example of this. Arenaria te7iuiJolia, Linn., was 

 first observed in 1897, but is now quite common along railways 

 in the central parts of Ireland. The genuine natives, on the 

 other hand, seem to be extending their range very slowly, or 



have disappeared from certain localities altogether. 



a3 



