PLANT DISTRIBUTION AND ASSOCIATIONS. 



XXV. 



In ascertaining to what extent each of these types is repre- 

 sented in the Halifax Flora, it is undesirable to deal with the 



whole body of plants enumerated for the parish, 

 Halifax but to attempt to eliminate erroneous and 



Flora. doubtful records, alien and casual plants, and 



various others, by which process the list is 

 reduced from some 760 species to about 560, the difference 

 being mainly due to plants which are only of casual occurrence 

 in this district, though most of them are more truly native 

 elsewhere in England. The residue represents much more 

 truly the proper flora of the parish, though in addition to 

 native plants, it includes denizens and colonists, as well as a 

 small number, possibly or certainly, now extinct. The follow- 

 ing table presents a summary of this reduced flora, analysed 

 according to Watson's classification, and compared with that of 

 Great Britain. The numbers make no claim to exactitude ; 

 there are too many dubious points to admit of a rigid compari- 

 son, but without laying too great a stress on the precise figures 

 arrived at, the conclusions to be drawn from them are 

 unaffected thereby, and are of considerable importance. 



Analysis of Types of Flora. 



* According to J. G. Baker in " Flora of the English Lake District." 



This analysis shows us that the Halifax flora contains four- 

 fifths of the plants of British type, that are found generally 

 distributed in Britain in suitable localities, and this class is so 

 dominant as to form three-quarters of the local flora. On the 

 other hand, only one-fifth of the plants of English type are 

 found here, and though they numerically rank second, it is 

 longo intervallo, and they are relatively not so well represented 

 as the Scottish plants. The weakness of the English type is 



