194 THE AMERICAN WATER-WEED. [September, 



field. Along this path it is met with at intervals of a quarter of 

 a mile. It grows in dry situations among the Brakes. 



" These two stations are upwards of two miles apart, and both 

 of them are a mile from any house. 



"W.H.Lucas." 



THE AMERICAN WATEE-WEED. 

 Anacharis Alsinastrum. 



To the Editor of the ' Phytologist. ' 



Sir, — In your last volume (i. n.s. p. 361) a correspondent throws 

 some doubt on my suggestions as to the apprehended mischief to 

 arise from this plant to navigation and drainage, and he says, 

 "he cannot see how it can obstruct the drainage of the Fens, 

 because it will not lie close enough together for even capillary 

 attraction to act so as to keep as great a bulk of water as itself 

 together." If your correspondent lived in a fen country, as I 

 do, he would soon know how Aveeds may and do impede the 

 drainage of rivers where, for many miles together, the fall is pro- 

 bably not more than four inches to a mile ; and when the ques- 

 tion is of navigation in such sluggish waters, he would soon see 

 that the Anacharis would increase in them almost as rapidly as 

 in a lake or pond. 



When I wrote some account of the Anacharis in 1852,'* it was 

 then but newly introduced into the Isle of Ely, and the question 

 then was, "How is it to be got rid of?" I ventured then to 

 answer that question with an emphatic " not at all," and subse- 

 quent experience has fully confirmed that prediction. Doubtless 

 it has gained a permanent footing with us, and can never be era- 

 dicated. Smothering our native water-plants, it takes exclusive 

 possession of ditches aijd drains, filling them completely with a 

 black-green mass, which gives quite a novel character to the 

 ditches in the Fens. I moreover ventured at that time to say 

 that all we could do would be to keep it down by raking it out 

 upon the shore ; and I warned commissioners of drainage against 

 letting fresh water from the rivers into their districts, for if they 



* ' The New Water-weed {Anacharis Alsinastrum) ; some account of it.' Bj 

 William Marshall, Esq., of Ely, Cambridgesliire. London : WiUiam Pamphn, 

 45, Frith Street, Soho Square. 



