NEBRASKA WILD-DUCK FOODS. 
57 
SUBMERGED PLANTS. 
Dominants: 
27. Variable pondweed (Potamogeton heter- 
ophyllus). 
28. Curly pondweed (Potamogeton per- 
foliatus richardsonii). Common. 
29. Bushy pondweed (Najas flexilis). 
30. Water smartweed (Polygonum amphi- 
tium). 
31. White water crowfoot (Batrachium 
divaricatum) .* Common. 
32. Coontail (CeratophyUum demersum). 
33. Spatterdoek (Nymphaea advena). 
Algae abundant. 
22. Musk grass (Chara sp.). 
23. Small pondweed (Potamogeton pusil- 
lus). 
24. Waterweed (Philotria canadensis).* 
Flowers ; only place found in this 
group of lakes in eastern Cherry 
County. 
Secondary species: 
25. Water moss (Drepanocladus sp.). 
Abundant. 
26. Sago pondweed (Potamogeton pectina- 
tus). Abundant. 
Wild-duck foods. — Plants in the above list which have considerable value as 
food for wild ducks are: Nos. 2 (16), 4 (20), 22, 23, 26, 27, 29, and 32; those 
of less importance are: Nos. 1 (18), 5 (17), 13, 19, 21 (30), 24, 28, 31, and 
33 ; the remainder are of no known value. 
TWENTY-ONE LAKE, CHERRY COUNTY. 
September 6, 1915. 
Description. — Marshy at west end. Water perhaps a little alkaline ; average 
greatest depth, 11 to 8 feet ; bottom, sandy. No inlet or outlet. 
Distribution of Vegetation, 
shore plants. 
Grasses, sedges, etc., as for other lakes, and in addition the following : 
1. Long-leaved reedgrass (Calamovilfa 
longifolia).* 
2. Big bulrush (Scirpus occidentalis). 
Abundant on wet shore. 
3. Sedge (Carex diandra).* Mature fruit. 
4. Mint (Mentha canadensis).* 
5. Goldenrod (Solidago altissima).* 
6. Groundsel (Senecio riddellii).* Flowers. 
SEMISUBMERGED PLANTS 
Dominant: 
7. Big bulrush (Scirpus occidentalis). 
Secondary species: 
8. Wapato (Sagittaria latifolia). Abun- 
dant. 
9. Reed (Phragmites communis). Abun- 
dant. 
10. Cord-grass (Spartina michauxiana) . 
11. Spike rush (Eleoeharis acuminata). 
Abundant. 
12. Water smartweed (Polygonum amphi- 
oium). 
SUBMERGED PLANTS. 
Dominants: 
13. Sago pondweed (Potamogeton pectina- 
tus). 
14. Curly pondweed (Potamogeton per- 
foliate richardsonii) . 
Secondary species: 
15. Floating pondweed (Potamogeton na- 
tans). 
16. Illinois pondweed (Potamogeton illi- 
noensis). 
17. Eelgrass pondweed (Potamogeton com- 
pressus). 
18. Small pondweed (Potamogeton pusil- 
lus). Abundant. 
19. Bushy pondweed (Najas flexilis). 
20. Coontail (CeratophyUum demersum). 
Common. 
21. Bladderwort (Utricularia vulgaris). 
Common. 
-. Algae abundant. 
FLOATING PLANTS. 
22. Big duckweed (Spirodela polyrhiza). i 24. Star 
duckweed 
Abundant. 
(Lemna trisulca). 
23. Small duckweed (Lemna minor). 
Wild-duck foods. — Plants in the above list which have considerable value 
as food for wild ducks are: Nos. 2 (7), 8, 13, 18, 19, 20, 22, 23, and 24; those 
of less importance are : Nos. 3, 10, 11, 12, 14, 15, 16, and 17 ; the remainder are of 
no known value. 
