THE PAGE OF NATURE. 201 



many years, slowly and almost insensibly adding layer 

 to layer, and attaining an enormous size, yet the vast 

 generality of fungi are very fugacious. They are the 

 ephemera of the vegetable kingdom. The entire life of 

 most of the species ranges from four days to a fortnight 

 or a month ; while there are numerous microscopic 

 species of the mould family whose lives are so brief and 

 evanescent as scarcely to allow sufficient time to make 

 drawings of their forms. What a contrast there is be- 

 tween the minute Bread-mould at the bottom of the 

 scale, and the gigantic Wellingtonia of the Oalifornian 

 forests at the top ! The one during the warm moist 

 weather of summer appears suddenly, as if by magic, 

 on a stale crust laid aside in a dark cupboard, attains 

 its highest development, ripens and scatters its seeds, 

 and perishes in a few days ; the other sent forth its 

 embryo shoots in the primeval solitude more than three 

 thousand years ago, and may yet witness the revolution 

 of many centuries ere it begins to decay. The largest 

 stalk of the Bread-mould is no thicker than a pin, and 

 may be half-a-liue or the twentieth part of an inch in 

 height ; the trunk of the Wellingtonia, like a huge 

 church-tower, rises nearly 300 feet into the sky, and 

 measures upwards of a hundred feet in circumference. 

 Why does this enormous difference exist 1 Why does 

 the fungus live for a day and the tree for ages 1 Why 

 does one seed produce a plant that has but a winter's, 

 or at most a summer's growth, and another grow into a 

 plant which endures for more than three thousand 

 years ? They are both composed of the same materials 

 a collection and combination of simple cells ; is it 



