Many plants of peaty soils e sclerophylious.
The soils of Florida have sand as a common ingredient.'
Again, the well-known action of earthworms may be said to be a biological work; but the resulting aeration of the soil causes edaphic differences; and earthworms are absent from certain soils, such as peat.
Halo phytes, or plants which live in saline soils, have xerophytic adaptations.
Tobacco is most generally cultivated on loose red soils, which are rich in clays and silicates; and sugar-cane preferably on the black and mulatto soils; but in general, contrary to prevalent suppositions, colour is no test of quality and not a very valuable guide in the setting of crops.
