34 NATURAL HISTORY OF PLANTS. 



plants. Putrescent animal substances are attacked by mucors, and 

 small fungi, which accelerate their destruction, and convert them 

 into earth, to afford soil and nourishment to other plants. Thus 

 the leaves, the stems, the wood, and different parts of vegetables 

 become a prey to these destructive fungi, which complete the pro- 

 cess of putrefaction. What appears to be nothing but desolation 

 and death, is the theatre of a new world in miniature. Every cre- 

 ated thing serves for the good of the whole. 



The plants of fresh water are more widely dispersed than those of 

 the land. Water moderates the heat and coid of climates, and hence 

 many European aquatic plants grow also in warm countries. The 

 common duck-meat (Lemna minor), grows not only over all Europe 

 and North America, but is found also in Asia. It has been observed 

 in Pennsylvania, Carolina, Siberia, Tartary, Bucharia, China, Cochin* 

 China, and Japan. The bulrush (Tjpha latifolia)^ grows over 

 Europe, North America, in Jamaica, in Siberia, China, and Bengal. 

 The great number of water-fowl- that yearly migrate, by a most 

 wonderful instinct, from a colder country to a warmer, occasions the 

 wider dispersion of aquatic plants. The most of these plants per- 

 fect their seeds at the season when the birds are preparing to set out 

 on their journey. The seeds stick to the feathers, they are also 

 sometimes swallowed by the birds, and afterwards passed without 

 injury. 



The plants that grow at the bottom of the sea are found in all 

 regions, because the vicissitudes of heat and cold are never felt at 

 the bottom, which is generally every where of the same tempera- 

 ture. The Fucus natans, a very common sea-plant, and which goes 

 by the name of sea-tang, or sea-grass, is found as well under the 

 equator as under the poles. As the marine plants are very nume- 

 rous, many of them are to be found every where, with this difference 

 only, that some require a more concentrated saltness of the water 

 or a moveable bottom. Others grow at different depths, and it is 

 only on such as prefer shallow water that the climate has any influ- 

 ence. In general it is to be remarked, that the heights or hills 

 which are found under the surface of the ocean, are more productive 

 of plants than the deep gulfs and valleys there. 



The mountainous or alpine plants are nearly the same on all those 

 chains which had formerly been connected, but are now disjoined,and 

 there are many that are common to different mountainous ridges, 



