text:  The plant that lives and sows its seed and dies has not only provided for its own progeny; under many circumstances it prepares the soil for successors of a superior rank of vegetation--"Pioneers of vegetation " as Dr Macculloch calls them "the lichens and other analogous plants seek their place where no others could exist; demanding no water requiring no soil careless alike of cold and heat of the sun and of the storm; rootless leafless flowerless; clothing the naked rock and forming additional soil for their successors