PROPAGATION OF WILD-DUCK FOODS. 
37 
Thirty-seven canvas-backs collected at Lake Surprise had eaten 
various parts of this plant to the extent of 71.6 per cent of their diet. 
This is a second illustration of the unusual phenomenon of the canvas- 
back's being attracted to shallow water by a highly prized food. 
Six ring-neck ducks, or blackjacks, made more than 91 per cent of 
their food of this plant, and two southern black ducks (Anas ful- 
vigula) 98 per cent. The following ducks also were feeding on the 
plant: Mallard, pintail, lesser scaup, redhead, and shoveller. The 
parts eaten are the rootstocks, stolons, tubers, and seeds. Mr. Charles 
W. Ward has furnished rootstocks of Castalia mexicana from Avery 
Fig. 
32. — Two types of leaves of banana waterlily. 
size.) 
(The larger outline half natural 
Island, La., with the information that this plant and wild celery 
(Vallisneria spiralis) furnish the bulk of the food of canvas-backs 
in that locality. 
DESCRIPTION OF PLANT. 
The banana waterlily is the only native species of the group of 
true water lilies (as discussed above) that has yellow flowers. But 
the leaves and flowers of this species may either float on the sur- 
face of the water or stand a few inches above it. The leaves are 
green above with brown mottlings and vary from greenish to purplish 
red below with small black markings. The edges of the cleft of the 
leaf are either somewhat separated or overlapping (fig. 32). The 
