554 THE UNIVERSE. 



encroaches upon nature, place a barrier to it. The first 

 invaders of a virgin soil are pitilessly stifled by those 

 Avhich follow them; the prairie gives way to a thicket, and 

 soon after this dies beneath the shady vaults of a vigorous 

 forest. 



The fecundity of some fungi is quite extraordinary. 

 Fries counted more than 10,000,000 reproductive bodies 

 in one individual of the Reticularia maxima. Other plants 

 of the same family I'ear a still larger progeny, the abund- 

 ance of which is prodigious, and which indeed cannot be 

 numbered by all the resources of the human intellect. 



The immeasurable fecundity of the gigantic Lycoperdon 

 is such that its microscopic grains must be counted by 

 thousands of millions. Now although they are invisible to 

 the eye- each of these may yet give birth to a voluminous 

 fungus which often in one night acquires the size of a 

 gourd. And it may be said, without hyperbole, that if 

 the little seeds of this plant were miraculously dispersed 

 over the whole globe, and were to be simultaneously 

 developed, the earth would be absolutely paved with 

 them the next day. 



The air certainly plays the most important part in the 

 dissemination of vegetable life. A host of Udit seeds 

 seem to have been decorated with little plumes and mem- 

 branous wings only in order to be Ijorne away by the 

 whirlwinds. 



For this purpose the seeds of many Syngenesiaj are 

 surmounted by plumes of outspread fibrilli?e, forming com- 

 plete parachutes which the slightest breath of the zephyr 

 l_)ears away. Tiirn from the mother plant, the seed, by 

 means of its aerial shift', accomplishes the longest jour- 

 neys. The slightest breeze carries it up from the depth 

 of the valley to the mountain peaks. If the tempest 



