Pkthybridge & Prakger — Vegetation South of Duhlin. 139 



work done in Scotland and England, and thus to start devoid of 

 preconceived notions as to what the associations (if any) might, 

 could, would, or should be, and to let them force themselves upon us 

 as they actually existed in this area. Some of our first days in the 

 field, therefore, were spent with no idea whatever of mapping, but 

 merely with a view to finding out whether associations did exist, and 

 sufficiently clearly so as to be capable of having their distribution 

 marked on maps. We were not long in recognizing that associations 

 did exist, and in deciding that they could be mapped, but only on a 

 map of a fairly large scale. Thus we determined from the first that 

 the six-inch-to-the-mile Ordnance maps were the only ones on which 

 the field-mapping could be properly done, and these we have used 

 throughout, each sheet being divided into four, and each quarter 

 folded once across for convenience in carrying in a suitable portfolio. 

 The only difficulty we have found in working with these maps is that 

 in some cases one is tempted to map in perhaps rather more detail 

 than one can really afford time for in a general survey^ so that the 

 progress is rather slower than it might be expected to be. Much of 

 this detail must of necessity be omitted in reducing the map to the 

 one-inch scale, the one we have adopted for publication; but 

 undoubtedly the boundaries of even the larger associations can be 

 much more accurately drawn on the six-inch map than on the one- 

 inch ; and it is certainly well to err on the side of having extra detail at 

 one's disposal than of having insufficient materials for a correct survey. 



In actually recording the distribution of the vegetation on the 

 maps in the field we found the best method was to use a series of 

 letters representing the dominant or sub-dominant species, and in 

 each spot to note down these letters in the order of frequency of the 

 plants ; and afterwards, in the face of the evidence of the whole 

 neighbourhood, to decide as to the boundary lines which the order of 

 these letters indicated. The series of letters used was as follows : — 



A = farm-land (crops and pasture). 



U = Ulex europcBus. 



G = Ulex Gallii. 



H = Erica cinerea. 



N = Nardus stricta. 



P = Fteris Aquilina. 



C = Calluna vulgaris. 



J = JimcHs spp. 



S = Scirpus ccsspitosus. 



E = Eriophorum spp. 



B = Racomitrium lanuginosum. 



V =r. Vaccinium Myrtillus. 



"W = mixed deciduous woods. 



E = Coniferous woods. 



In the case of all characteristic associations, presided over by one 

 or more of these plants, or by other species not mentioned above, lists 



K. I. A. PROC, VOL. XXV., SEC. H.] N 



