. Bulletin. Natural history; Natural history. 266 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 8 Fig. 27.—Nutgrass (Cy- perus sirigosus). This de- sirable source of duck food grows on mud flats. Chufa (Cyperus esculenlus) is very similar but a better duck food because it produces tubers as well as seeds, on both of which ducks feed. The inset shows a bed of red- rooted nutgrass (Cyperus ery- Ihrorhizos) flooded by fall of 20 acres in Muscooten Bay had only one fruiting head per 16 linear feet in August, 1939. Two acres of giant bur- reed in Goose Pond in the same month had on
. Bulletin. Natural history; Natural history. 266 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 8 Fig. 27.—Nutgrass (Cy- perus sirigosus). This de- sirable source of duck food grows on mud flats. Chufa (Cyperus esculenlus) is very similar but a better duck food because it produces tubers as well as seeds, on both of which ducks feed. The inset shows a bed of red- rooted nutgrass (Cyperus ery- Ihrorhizos) flooded by fall of 20 acres in Muscooten Bay had only one fruiting head per 16 linear feet in August, 1939. Two acres of giant bur- reed in Goose Pond in the same month had one fruiting head per 3 linear feet. The first bed was located in an area with more rapidly fluctuating waters than was the second. Hutchens reports (letter, Jan. 8, 1941) that at McGinnis Slough in Cook County no seed was produced by giant bur-reed plants growing in water. Those growing on moist soil produced seed. The plants growing in water were 3 to 4 weeks later in development than those growing on moist soil. Sago pondweed, fig. 22, is an erratic seed producer in the Illinois River valley. Often rated as one of the most valuable duck food plants, it falls short of this repu- tation in the Illinois valley because of its failure to produce seed in certain years. In 1938, inspection showed that longleaf pondweed beds in Lake Chautauqua, fig. 24, were producing fully twice as much seed as were sago pondweed beds of equal size. A study involving use and abundance of duck foods (Bellrose& Anderson 1940) corroborated this finding. Although at Lake Chautauqua sago pondweed pro- duced more seed per plant in 1939 than in the previous year, the seed it produced in 1940 was approximately as much as in 1938. At Siebolt's and Sawmill lakes, sago pondweed produced little seed in 1940 notwithstanding the abundance of plants in those lakes, table 2. According to estimate, less than per cent of the plants at these lakes, and at Goose Pond in 1940 only per cent of the plants, ha
Size: 1690px × 1479px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
