xcvi INTEODUCTION 



such a classification by means of lines defining the area included 

 in divisions 1-10, 11-20, 21-30, 31-40. Thus it will be seen that 

 a glance along the census-line and down the list of division-numbers 

 will at once give the key to the distribution of any species in 

 Ireland. 



List of divisions. — The order in which the divisions are enu- 

 merated has already been explained ; the longer names are contracted 

 in a way which will be easily intelligible. The inclusion of a divi- 

 sion and its accompanying record in parenthesis signifies either that 

 the plant is believed to be now extinct in the division, or that, in 

 comparison with other records, its occurrence in the division has 

 little phy to -geographical importance, on account of probable intro- 

 duction or non-permanency. Parenthesis accompanied by a note of 

 interrogation signifies a doubt as to the occurrence of the plant at 

 all, and implies possible or probable error. 



The records. — The general plan has been explained above. The 

 signs *, :|:, f , are used as already noted. When a plant, possibly or 

 probably introduced in Ireland, varies in standing according to the 

 authorities quoted, these signs are often attached to the different 

 stations, and signify the opinion of the person whose name is 

 appended to^ the record. In such cases, the absence of one of the 

 qualifying signs does not necessarily imply that the finder considered 

 the plant native, but only that he did not attach a qualifying sign. 



The note of exclamation (!) signifies as usual that the record is 

 backed by the personal knowledge of the compiler. When prefixed 

 to the name of a p^ace it implies that I have seen the plant growing 

 in the station mentioned ; when prefixed to the name of a person or 

 ■herbarium it means that a specimen from the spot named has been 

 -examined (or in the case of a critical plant, submitted by me to an 

 authority). 



Square brackets in all cases signify editorial additions. Where 

 the recorder of a plant is a person different from the finder, the name 

 of the latter is printed in parenthesis. When the name of a book is 

 given as the authority, this is not resorted to, as no confusion of 

 names is then probable. 



Italic type is used for the reference numbers of papers, &c., as 

 ■they appear in the Bibliography ; for the names of books ; and for 



