392 SCIENCE PROGRESS 



and anatomist, are contributed by Prof. Farmer to the Proc. 

 Roy. Soc. vol. xc. p. 218). The author has estimated the 

 conductivity of the wood in trees and shrubs by the volume 

 transmitted during fifteen minutes through a length of 1 5 cms., 

 with a pressure of 30 cms. of mercury. The conductivity per 

 unit area of evergreens (specific conductivity) was found to 

 be relatively low with slight variation, whilst that of decidu- 

 ous trees is high with marked fluctuation. Thus Euonymus 

 japonicus gave an average of 1 2, with a range of ± 6, whilst 

 its deciduous congener the spindle-tree gave 47 ± 8. Young 

 or immature wood always gave a low conductivity, and 

 the low conducting power of " leaders " as compared with 

 lateral shoots is suggested as a factor inducing sympodial 

 growth. The effect of manuring on fruit trees is to increase 

 the conducting capacity, and root-pruning appears to induce 

 a decrease. 



Adamson {Jour. Ecology) describes some associations of 

 the Southern Pennines. The cotton-grass moors, character- 

 istic of deep ill-drained peat, are regarded as the outcome of 

 post-glacial conditions, and to be now, generally, in a decadent 

 condition. This latter has brought about a new succession 

 of phases, dominated respectively by Deschampsia flexuosa, 

 Nardus stricta, Vaccinium myrtillus, and Calluna vulgaris, 

 exhibiting progressive increase of peat. 



In the Transactions of the New Zealand Institute, vol. 1., 

 Prof. Wall considers the interesting problem of the distribution 

 of the closely allied Senecio lagopus and S. saxifragoides, which 

 only differ in the relative abundance and distribution of their 

 hairy covering. Despite their close affinity each, in its own 

 rather wide but well-defined area, retains its individuality, 

 S. lagopus being found over the main mass of Banks Peninsula, 

 whilst S. saxifragoides is absent from this area, but occurs, 

 unaccompanied by its congener, upon the Port Hills, where 

 the peninsula abuts upon the mainland. It is suggested that, 

 since the Akaroa peaks, on which the less hairy S. lagopus 

 flourishes, are moister and subject to a higher rainfall than 

 the Port Hills, the two plants may be in the nature of climatic 

 microspecies. 



Our scanty knowledge of the ecology of Cryptogams has 

 been enriched by an account of the cryptogamic vegetation of 

 the sand-dunes of the West Coast, particularly Devon and 



