ELEVEN IMPORTANT WILD-DUCK FOODS. 5 



PROPAGATION. 



The seeds of duckweeds are minute and seldom mature. The 

 plants, therefore, must be transplanted bodily. There is no diffi- 

 culty about this, for if they are not crushed or allowed to ferment 

 or dry, duckweeds are perfectly at home from the moment they 

 are placed in a new body of water. Fermentation may be prevented 

 by shipping in small units freely exposed to the air. Plants which 

 are to be transported a long distance should be iced. 



It is useless to put duckweeds in large open bodies of water. 

 They thrive best in small pools and ditches where the water surface 

 is rarely disturbed. In ponds entirely surrounded by forest growth 

 and wooded swamps duckweeds also abound, but they are equally 

 at home in small pools and other openings among the reeds and 

 sedges of marshes. They are strictly fresh-water plants. 



FROGBIT. 

 VALUE AS DUCK FOOD. 



Frogbit and the three species next described (thalia, water elm, and 

 swamp privet) are at present known to be of only local importance 

 as wild-duck foods. Frogbit is an abundant inhabitant of some 

 of the shallow cypress-margined lakes in Avoyelles Parish, La. It 

 produces spherical fruits filled with gelatinous matter in which are 

 a multitude of seeds, eagerly sought by ducks. Nearly 18 per cent 

 of the food of 308 mallards collected in that locality from October 

 to March, inclusive, consisted of these seeds. From 8,000 to 10,000 

 were found in each of several stomachs and one contained 32,000. 

 Other ducks found feeding on frogbit seeds were the pintail and 

 ringneck. Twenty-five stomachs of the latter species collected in 

 December contained on the average over 35 per cent of these eagerly 

 sought seeds. 



DESCRIPTION OF PLANT. 



Frogbit (Limnobium spongia) floats in shallow waters, extending 

 its roots into the muck below, or it may grow on soft mud itself. 

 On stalks from a few inches to a foot in length are several heart- 

 shaped leaves (fig. 3), which have 5 to 7 longitudinal veins springing 

 from the base, and numerous cross-veins. The underside of the 

 leaves is sometimes purplish. Numerous spongy runners help to 

 support the plant in the water, and they also form new plants at 

 the joints. The flowers emerge from conspicuous sheaths, and appear 

 to have 3 sepals which are broader and sometimes reflexed and 3 

 petals which are narrow and more erect. The stamens, 6 to 12 in 

 number, are given off at different heights from a central column. 

 The stalks supporting the berrylike fruits are thick and recurved. 

 The berry, as previously noted, is filled with a mixture of seeds and 



