GEOGRAPHICAL DISTRIBUTION. 45 



one or another species, according to the season of the year, 

 or the nature of the soil, or other material on which they 

 thrive. AVith reference to this latter point there is con- 

 siderable variety among Mosses, though not so much as we 

 find among higher plants. Some species prefer clay, and 

 others peat ; one genus affects sandstone, and another cal- 

 careous rocks, while several are found chiefly on particular 

 species of trees. Mr. Spruce, in his interesting paper on the 

 " Mosses of Teesdale," published in the Transactions of the 

 Botanical Society of Edinburgh, observed however that in 

 that district " very few of the Mosses were absolutely con- 

 fined" to either the basaltic or limestone clifl's of which it 

 is composed. In speaking of the varied localities in which 

 particular genera or species are found, Drs. Hooker and 

 Taylor, in the preface to their interesting ' IMuscologia Bri- 

 tannica,^ make the following remarks : — " One curious little 

 plant is found only on the perpendicular faces of the pui'e 

 white chalk-pits that abound so much in Kent and Sussex. 

 Some are confined to granite, some to calcareous rocks ; 

 one species, the Fnnaria hygrometrica, a moss that grows in 

 all parts of the world, is almost sure to spring up where 

 anything has been burned upon the ground, and particu- 

 larly where charcoal has been made, whence its Trench 



