PROPAGATION OP WILD-DUCK POODS. 



13 



stocks and will soon make a dense growth. The winter buds or 

 pieces of roots with tufts of leaves must be weighted to hold them 

 to the bottom and enable them to take root. This may be accom- 

 plished by loosely threading several plants together and tying stones 

 to them, or by embedding them in balls of clay. The broken seed 

 pods also may be put into clay and dropped. 



When to plant. — Where not likely to be covered by mud, the best 

 time to sow the seed pods is in fall. Winter buds collected in fall 

 should be kept in cold storage, and these, as well as young plants 

 gathered in spring, should be set out in May or June. 



Fig. 7. — Range of wild celery. (Black spots show where it has been successfully trans- 

 planted. Crosses indicate States in which it has been propagated, the exact localities 

 being unknown.) 



PONDWEEDS. 



VALUE AS DUCK FOOD. 



Pondweeds (Potamogeton) compose a greater percentage of the 

 food of wild ducks than wild rice and wild celery together. This is 

 due to the wider distribution of pondweeds, allowing ducks to feed 

 on them in winter as well as during migration and in the breeding 

 season. There are no fewer than 38 species of pondweeds in the 

 United States, of which at least nine (figs. 9-17) are of practically 

 universal distribution. One of the number, the fennel-leaved or 

 sago pondweed (P. pectinatus, fig. 17) , produces upon the rootstocks 

 numerous tubers (fig. 18) which are eagerly sought by certain ducks. 



This one species makes up five-eighths of the whole quantity of 

 pondweeds eaten by the canvas-back and more than a fourth of the 



