XX vi. THE FLORA OF HALIFAX. 



due much more to the elevation of the parish, rather than to its 

 latitude, and many of this type are confined here to the lowest 

 part of the parish, as is shown later. Nor is the tenure of a 

 considerable proportion of them secure, even there. For not 

 only are they liable to be disturbed by the growth of the towns, 

 but many of them, the weeds of cultivated and waste ground, 

 are sometimes hardly to be distinguished from casual introduc- 

 tions. This is borne out by the fact that the list of casuals, so 

 far excluded from consideration, is exceptionally rich in plants 

 of English type, the aggregate being half as large again as the 

 number admitted into the table. 



The plants of Scottish type rank third in number, but 

 occupy a much more important position than in the flora of 

 Britain as a whole. Excluding from consideration such High- 

 land plants as are confined to the lofty mountains of Scotland, 

 the flora of Halifax, in the relative strength of species of 

 Intermediate, Scottish and Highland type, shows a much 

 greater resemblance to that of North Britain than of the South 

 of England. This might be expected from the situation of the 

 parish on a chain of hills, practically continuous into Scotland, 

 but disappearing southwards in Derbyshire. 



The Germanic type may be said to be conspicuous by its 

 absence, though casuals of this type are sometimes introduced 

 with grain. But the moist, sheltered doughs in the western 

 part of the parish are certainly suitable habitats for plants of 

 the Atlantic type, as shown by the presence of Cotyledon (per- 

 haps introduced), Hymenophyllum (extinct), and Wahlenbergia, 

 and emphasised by the discovery, by Mr. Needham in 1896, of 

 a typical Atlantic-type hepatic, Jubala Hutchinsice, near Hard- 

 castle Crags. 



The last deduction to be drawn from this analysis of the 

 types of plants represented here, and it is only derived from an 

 examination of the individuals composing the classes, is that 

 whatever plants have become, or are in danger of becoming, 

 extinct, do not belong to the British type, but rather to the 

 others. This is perhaps due to the fact that the plants of the 

 other types are frequently not present in large numbers individ- 

 ually, though of course, in many cases they are abundant 

 enough. And though some of these rarest ones still grow in 

 the exact localities from which they were first recorded, such 

 changes as have taken place are in the direction of the diminu- 

 tion of every one of the other types, (unless it be the Interme- 

 diate,) and the supremacy of the British type. 



