22 
BULLETIN 205, U. S. DEPARTMEXT OF AGRICULTURE. 
Waters in which it is found are usually cool and have some current. 
It may be sown in similar situations at any time during spring 
or summer. 
WATER-WEED. 
VALUE AS DUCK FOOD. 
Evidence for the value of water-weed is of the same nature as for 
water-cress. The density and luxuriance of its growth are such that 
water-weed maintains its stand even when fed upon daily b}" a large 
number of ducks. Small quantities of the plant have been found in 
stomachs of the mallard, blue-winged teal, and goldeneye. 
DESCRIPTION OF PLANT. 
Water- weeds (figs. 19 and 20) have long, branching steins with 
luxuriant foliage and are of a beautiful translucent green color. The 
leaves, which are set upon 
the stem in whorls of from 
2 to 4 (usually 3), vary 
from ovate to strap-shaped, 
and may be pointed or ob- 
tuse, and are sometimes 
finely toothed. They are 
from one-fourth to one inch 
or more in length and from 
one-twelfth to one-eighth 
of an inch in width. The 
small flowers are borne on 
rather long stalks and open 
at the surface of the water. 
The fruit, which is rare, is 
few seeded and ripens un- 
der water. 
This plant was intro- 
duced into Great Britain 
in the middle of the nine- 
teenth century, and spread 
rapidly, making such rank growth that it soon became a pest, filling 
ornamental waters, mill races, and canals. It became known there 
as American water- weed and Babington's curse (because introduced 
by a botanist of that name). Other names applied to the plant are 
ditch-moss, water-thyme, thyme-weed, cats-tails, and choke pond- 
weed. 
Some botanists consider that there are several different species of 
water-weed in the United States. But, having in mind the entirely 
different aspect wild plants of water-weed assume when transferred 
to an aquarium, one is inclined to think that differences in the forms, 
Fig. 19.— Water- weed. A compact form. 
