424 
in fact—but below the group consisting 
principally of nodding, large-seed and 
swamp smartweed. 
The relative value of the three species 
of nutgrasses may be judged by the fol- 
lowing facts: Cyperus erythrorhiz0s, 
represented by 56.5 per cent of the total 
nutgrass seed found in duck gizzards, 
was much more abundant than C. sért- 
gosus, represented by 19.0 per cent of 
the nutgrass seed; C. esculentus, how- 
ever, made up 24.5 per cent of the total 
nutgrass seed, even though less abun- 
dant than C. strigosus. This would in- 
dicate that C. esculentus was slightly 
better than C. erythrorhizos, which, in 
turn, was better than C. strigosus. 
Moist-soil smartweeds, consisting 
of largeseed smartweed, Polygonum 
pennsylvanicum, fig. 4, nodding smart- 
weed, P. lapathifolium, fig. 5, swamp 
smartweed, P. hydropiperoides, and 
minor quantities of other species, rank 
fourth for the 3-year period, table 3. 
However, here also the same factors 
prevail that were responsible for an 
error in the index value of the nut- 
grasses: in many places seeds deposited 
Fig. 6.—Japanese millet (Echinochloa fru- 
mentacea) under favorable growing conditions 
is one of the greatest seed producers among the 
duck food plants of the Illinois River valley. 
Because its seed production is greatly depend- 
ent on growing conditions, its comparative 
value ranges from excellent to fair in the course 
of several years. 
Ittinoris NatuRAL History SURVEY BULLETIN 
Vol. 22, Art. 5 
in one year were consumed the next, 
when germination did not occur and 
plants were not recorded. The 1940 
index rating of 2.43 in table 6 is probably 
the most nearly accurate It places 
these species slightly above the nut- 
grasses in value. 
Wild and Japanese millets, Echi- 
nochloa crusgalli and E. frumentacea, fig. 
6, appear fifth in order of preference in 
table 3, covering 1938, 1939 and 1940. 
For some reason, waterfowl did not ob- 
Fig. 7.—Giant bur-reed (Sparganium eury- 
carpum) ranks sixth as a duck food plant in the 
Illinois River region. Its value here is con- 
siderably higher than it is generally accorded 
elsewhere. The globose heads are composed of 
nutlike, beaked seeds that are eaten by ducks. 
tain appreciable amounts of seed of 
these species from mud flats in 1938. 
Had they done so, the status of these 
millets would undoubtedly have been 
raised above that of the smartweeds. 
Table 6 shows that Japanese and wild 
millets headed the list in 1940, when 
they were slightly better than rice cut- 
grass. 
As in other species, millets vary in 
seed yield with habitat conditions. 
Furthermore, time of planting greatly 
affects seed production. Japanese mil- 
let sown in the Illinois River valley after 
