Ixx INTEODUCTIOlSr. 



tlie defined limits is by no means continuous. "With the wider 

 ranging species, Saxifraga umhrosa, Mtphorhia hiberna, and Mrio- 

 eaulon septrngula/re, it is, indeed, remarkably discontinuous ; and the 

 longer breaks in the range of these plants are indicated by carrying 

 out to sea the appropriate curved line for each. For instance, 

 Euphorlia Ulerm, the Irish Spurge, is shown to have a fairly con- 

 tinuous range m the south-west, to disappear for a long interval in 

 the west, where it occurs only in the island of Inishturk, and to 

 re-appear for a space in northern Donegal. The known Irish area 

 occupied by some of the species is so inconsiderable that they cannot 

 properly be said to have any range, and the position of these is 

 indicated by a loop {Inula salioma), or even by a dot {Arenaria 

 eiliata) . The remarkable restriction of the Hibernian type plants to 

 the west and south-west of the island was first shown by this system 

 of distribution curves iu the original edition of this work. In the 

 present, the curves have been cai-efully revised, so as to bring 

 them into conformity with the latest information. 



X. EXPIANATOET NoTES ON THE TeXT. 



Nomenclature. — In revising for this second edition the nomen- 

 clature adopted in the first, the law of priority has not been 

 invariably followed. A widely familiar and long established name 

 has always been allowed to stand when the only reason to be urged 

 against its retention was the existence of an earlier published name, 

 long siuce become obsolete or never admitted to general currency. 

 Whatever may be the final result of the resuscitation of such 

 obsolete or still-born names iu obedience to the strict letter of the 

 law of priority, the immediate effect must be to cause that confu- 

 sion which the law was designed to prevent or to remove. The 

 present work makes no claim to be regarded as an authority in 

 nomenclature. It seeks to be intelligible and easy of reference for 

 all who are likely to make use of it ; and these ends, it seems to 

 the editors, may best be secured by retainiag, despite of their 

 illegality, many well-known and long-established names. These 

 names are, perhaps, doomed to extinction in the not very distant 

 future ; but it may be confidently predicted that they vrill remain 

 famiHar long after this work has served its pm-pose and been laid 

 aside as obsolete. 



Native Plant Names. — As a rule, only such native names as are 

 widely current m the Irish-speaking districts of Ireland have been 



