376 HOW CROPS GROW. 



merged in water. Many forms of vegetation found in 

 our swamps and marshes are of this kind. Of agricul- 

 tural plan ts, rice is an example in point. Rice will grow 

 in a soil of ordinary character, in respect of moisture, as 

 the upland cotton-soils, or even the pine-barrens of the 

 Oarolinas. It flourishes admirably in the tide-swamps of ' 

 the coast, where the land is laid under water for weeks 

 at a time during its growth, and it succeeds equally well 

 in fields which are flowed from the time of planting to 

 that of harvesting. (Eussell, North America, its Agri- 

 culture and Olimate, p. 176.) The willow and alder, 

 trees which grow on the margins of streams, send a part 

 of their roots into soil that is constantly saturated with 

 water, or into the water itself ; while others occupy the 

 merely moist or even dry earth. 



Plants that customarily confine their growth to the 

 soil occasionally throw out roots as if in search of water, 

 and sometimes choke up drain-pipes or even wells by the 

 profusion of water-roots which they emit. At Welbeck, 

 England, a drain was completely stopped by roots of 

 horse-radish plants at a depth of 7 feet. At Thprnsby 

 Park, a drain 16 feet deep was stopped entirely by the 

 roots of gorse, growing at a distance of 6 feet from the 

 drain. [Jour. Roy. Ag, Soc, I, p. 364.) In New 

 Haven, Connecticut, certain welte are so obstructed by the 

 aqnatic roots of the elm trees as to require cleaning out 

 every two or three years. This aquatic tendency has 

 been repeatedly observed in the poplar, cypress, laurel, 

 tuirnip, mangel-wurzel, and various grasses. 



Henvici surmised that the roots which most cultivated 

 plants send down deep into the soil, even when the latter 

 is by no means porous or inviting, are designed especially 

 to bring up water from the subsoil for the use of the 

 plant. He devised the following experiment, which ap- 

 pears to prove the truth of this view. On the 13th of 

 May, 1862, a young raspberry plant, having but two 



