PROPAGATION OP WILD-DUCK FOODS. 



17 



The species of ducks and swans thus far found to feed upon pond- 

 weeds are the following : Sheldrake, red-breasted merganser, hooded 

 merganser, mallard, black duck, Florida duck, gadwall, European 

 widgeon, American widgeon, green-winged, blue-winged, and cin- 

 namon teal, shoveller, pintail, wood duck, redhead, canvas-back, 

 greater and lesser scaups, ring-necked duck, golden-eye, buffle-head, 

 white-winged and surf scoters, ruddy duck, and whistling swan. 



DESCRIPTION OF PLANTS. 



The most important species, so far as known, is the sago pondweed 

 (Potamogeton pectinatus) . This plant has numerous, rather long, 

 threadlike leaves, which present 

 a loose, broomlike appearance in 

 the water. The plant is in some 

 places known as foxtail grass. 

 It is known also as eelgrass, and 

 apparently is the plant termed in 

 Europe poker or pochard grass, 

 after a duck closely related to 

 "our redhead. In autumn sago 

 pondweed bears small clusters' of 

 light-brown seeds or nutlets near 

 the surface of the water, in form 

 somewhat like loose bunches of 

 grapes. The other pondweeds 

 bear seeds in the same way, and 

 vast numbers of them are eaten 

 by ducks. 



The general appearance of 

 sago pondweed is well shown by 



figure 17; note the brush of fine Fig. 17.— Sago pondweed. (Reduced. From 



threadlike leaves and the seed Sunset Ma s azilie > February, 1905.) 



clusters as above described. Here also are shown the tender root- 

 stocks with their tubers, delicacies much sought by many ducks. 

 Figure 18 illustrates the tubers natural size. 



All pondweeds of the pectinatus group have tubers, and may there- 

 fore be substituted for sago pondweed for propagating purposes. 

 These species are similar in general appearance and hardly dis- 

 tinguishable by the layman. The scientific names and general ranges 

 of the species in the pectinatus group are as follows:, 



Potamogeton flliformis Northern States, Southern Canada. 



Potamogeton interior Ontario, British Columbia, Colorado, Utah. 



Potamogeton latif otitis California, Nevada. 



Potamogeton interruptus Michigan, Saskatchewan, Nebraska. 



61718°— Bull. 465—17 3 



