in Open- Air Gardening in the Riviera. 349 



a plant's requirements, or evidence of response to different 

 environments in its external morphology. It may be that 

 this is mainly a question for the botanist, and that there is 

 no likelihood of more than an infinitesimal gain in the prac- 

 tical details of horticulture from knowledge under this head. 



We are well aware what a risky and thankless task it is 

 to put forward hypotheses to account for facts which all are 

 ready to receive ; but we would venture on a hypothesis in 

 regard to this subject. It is as follows : — The Sphagnum, 

 apparently so unsuited as a medium for the growth of Erica, 

 Epacris,IIardenhergia, Primula sinensis, &c., in Britain, is in the 

 Eiviera kept sweet and wholesome, though more often watered 

 it may be, by reason of the vastly warmer and drier climate. 

 In Britain, just the same nutriment, and the same loose 

 substance as a compost, might be given to the plants as is 

 given in the Eiviera, yet it cannot be imagined that there 

 would be the same amount of circulation of the water held 

 by the investing medium about the plants' roots. Conse- 

 quently, in place of sweetness, there would be sourness and 

 stagnation. We would even say that the same amount of 

 direct sunshine and the same amount of warmth might be 

 given to these plants, supposing we were to grow them in 

 Sphagnum in Britain as we do in the Riviera, yet in the 

 greenhouse in Britain there would not be that dry air, that 

 absence of humidity, and that freshness of the wind which 

 here causes quick evaporation ; and hence it would appear 

 improbable that the food about the plants' roots could be 

 presented in a suitable way by using Sphagnum in England, 

 though it may well be used here. 



We come to a similar conclusion in reference to the 

 different habitats of the same species of plants as observed 

 growing in Lapland and at the Yugor Straits. Soils, whether 

 of peat or clay or sand, had little meaning, except inasmuch 

 as they retained or drained off the water resulting from the 

 melting of the snows or from rain. In Lapland a steep hill- 

 side covered with peat answered much the same purpose as the 

 nearly level tracts of sand along the shore of Northern Siberia. 



However this may be, such facts of distribution or of 

 cultural methods should teach us something to be put to use 

 some time as to the adaptability and the requirements of our 

 garden plants. 



