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Reviews and Book Notices. 



area, some of the species so characterised being recorded only 

 as weeds in cultivated ground or waste heaps and gardens (see 

 pp. 88, 90, 91, 94, 95, etc.). Even if these may be claimed as 

 natives in Britain (which is doubtful), the Halifax parish is 

 surely a most unlikely area to produce them as such. In an 

 area of this kind all species which maintain their existence only 

 in ground specially prepared for them by man, competition 

 by other plants being prevented, should be regarded with great 

 suspicion, and we regret the authors have not adhered more 

 rigidly to this rule, especially when the point of view is that 

 of plant associations, for we believe that an important feature of 

 this method of study will be to enable us to distinguish more 

 clearly than we have hitherto done natives from species of lower 

 grades of citizenship. It is a distinct loss to British botany that 

 this method was not adopted generations ago when, in 1836, 

 H. C. Watson"^ advocated the making of vegetation maps as 

 distinct from maps showing the distribution of orders or species. 

 Unfortunately his suggestions were not acted upon, and the 

 paper seems to have been almost forgotten or unknown. After 

 a lapse of nearly 70 years the method was applied in Scotland and 

 now in England. Better late than never. 



We should like to have seen a vegetation map included in 

 this flora. The use of signs as suggested by Watson would 

 have been both effective and inexpensive. 



One feature brought out in this area is the fact that the 

 moors, to a great extent, are occupied by cotton grass. As 

 they point out, the popular belief is that a moor is a rolling 

 stretch of heather, though, in fact, on many extensive moors, 

 pre-eminently in Halifax, heather is conspicuous by its absence, 

 a feature which was first called attention to by Mr. C. E. 

 Moss. Curiously enough, although this work furnishes 

 abundant evidence that the flora of the parish has undergone 

 considerable changes, it does not seem to have occurred to 

 the authors to inquire more deeply into this old and popular 

 belief, and consider the very strong evidence that exists that 

 our present cotton-grass moors have developed enormously 

 in extent within quite recent years, and also the fact that, in 

 adjacent areas at any rate, they are going back again to their 

 earlier condition. We are glad to learn that cotton-grass is 

 not a grass, but a sedge. We suppose this is a set-off 



* ' Observations on the Construction of Maps for illustrating- the Distri- 

 bution of Plants.' Hewett C. Watson, Mag. Nat. Hist., 1836, p. 17. 



Naturalist, 



