398 Scientific Proceedings, Royal Dublin Society. 



spinosa, Veronica arvensis, Fumaria officinalis, and Achillea Millefolium. The 

 Veronica and following two plants are usually found on alkaline soil, whereas 

 here it was acid, pH 6"0. 



Further examples of lowland acid soil are furnished by the banks of the 

 Blackwater. On the western side the banks slope down steeply to the road. 

 They are wooded, the trees being conifers, oaks, and mountain ash for the 

 most part. Here the soil is peaty and as acid as pH 4'6, grading down to 

 pH 6"4 in the ditch beside the road, a distance of a few feet. The peaty soil 

 is covered with Erica cinerca and Calluna vulgaris. A certain amount of 

 earth was, however, mixed with it in most parts the reaction being about 

 pH 5'0 with both varieties of heather, Scilla nutans, Pteris aquilina, 

 Vacoinium Myrtillus, and on rocky ledges Polytrichum commune and Peltigera 

 canina, also at pH 5. A drop of four to ten feet brings one to the grassy 

 bank bordering the road. Here are found R. fruticosvs, P. aquilina, Jadone 

 montana, Viola canina, Lonicera Periclymenum, with stray small plants of 

 Erica cinerea and Calluna vulgaris; this soil, which is more earthy than 

 peaty, is at pH 5-8. Further along the same bank was at pH 6-4, and 

 supported U. euroiMcus, J. montana, Aspidium sp., also Agrimonia Eupatoria, 

 var. odorata, Mill. The absence of heather and bracken may be noted. The 

 drain by the road was also at pH 6'4, and the bare earth was dotted with 

 Bellis perennis and a small white clover. On the opposite side of the river 

 the flora was very similar, though the sloping fields were not wooded at the 

 spot examined. The earthy soil was at pH 5 '8 on the bank and pH 5-4 in a 

 dry field, from which both Calluna vulgaris and Scilla nutans were absent. 



Upland acid soils may be illustrated by the peat of Glencullen at about 

 1,200 ft. altitude in Co. Dublin. This peat is at pH 4-6 ; both Calluna 

 vulgaris and Vaccinium Myrtillus abound. One sample from Crib Goch, 

 Snowdon, was at pH 5'0, the soil being earthy rather than peaty, and covered 

 with grass, lichens, and also Lycopodium Selago. For these two soils the 

 writer is indebted to Mr. L. B. Smyth. 



Samples from Dartmoor were found to be very uniformly at pH 5"4-5'l, 

 and were carefully compared against drops of standard buffer solutions on 

 porcelain. Thus, at Staple Tors, both the drier earthy soil supporting E^-ica 

 Tetralix and Anagallis tenella, and wetter portions with Sphagnum sp., 

 Narthecium ossifragum, and Drosera rotundifolia, were at pH 5'4. At 

 Merrivale, about a mile away, an earthy soil with plant remains was grass- 

 covei'ed in the drier parts, and as acid as pH 5'2, the wetter parts with 

 Eriophorum polystachiooi and Sphagnum sp., being at pH 5-4. The most acid 

 soil as yet encountered was obtained from the crevices in a wall of piled 

 granite here. On it grew mosses, a liverwort, and Jasionc montayia. It 



