56 PLANTS FOli THE 



Thames," quote a pamphlet by William Marshall, Esq. 

 where, when speaking of the Anacharis, lie says — " The in- 

 truder is so unlike any other water-plant, that it may be 

 at once recognized by its leaves growing in threes round a 

 slender stringy stem. The color of the plant is a deep 

 green ; the leaves are about half an inch long by an eighth 

 wide, egg-shaped at the point, and beset with minute teclh 

 which anise, them to cling, so that wheucver the plant is dis- 

 turbed fragments arc broken off. Although it cannot at 

 present propagate itself by seed (all the flowers being male) 

 its powers of increase are prodigious, as every fragment is 

 capable of becoming an independent plant, producing roots 

 and stems, and extending itself indefinitely in every direc- 

 tion. Most of our water-plants require, in- order to their 

 increase, to be rooted in the bottom or sides of the river 

 or drain in which they are found ; but this is independent 

 altogether of that condition, and actually grows as it travels 

 slowly down the stream, after being cut," That this weed 

 is "a foreigner" to England there can be little doubt. Its 

 property of " holding on," and, as it were, crying, " don't 

 give up the ship," marks it as an American. And again, 

 " weeds very closely resembling, if not identical with it, are 

 found in American rivers. Mr. Marshall is of opinion that 

 it is an importation from North America : and that, pro- 

 bably, its first visit was paid to us in a load of American 

 timber. ITc considers that all attempts to 'get rid of it' 

 must be futile ; that it never can It eradicated : and that all 

 we shall be able to do is to ' keep it down.' Its rapid 

 growth is one of the marvels of nature. It is becomin"- 

 a serious evil : the Commissioners of the Thames should lose 



