14 BULLETIN 862, U. S. DEPARTMENT OF AGRICULTURE. 
nearly filled with the small individual plants, or thalli, of a duck- 
weed (Lemna sp.). These plants are very abundant in many of the 
localities from which the baldpates were taken, but for some reason 
other foods seemed to appeal to them more strongly. 
SMARTWEEDS (POLYGONACEAE), 1.47 PER CENT. 
The seeds of water smartweed (Polygonum amphibium) were pres- 
ent in 11 baldpate gizzards, those of dock-leaved smartweed (P. 
lapathifoltum) in six. Others identified were knotweed (P. avicu- 
lare), water pepper (P. hydropvper), and lady’s-thumb (P. persicaria), 
each in two, and mild water pepper (P. hydropiperoides) and black ~ 
bindweed (P. convolvulus), each in one. The fact that the seeds of 
smartweeds are the only edible parts of these plants probably is the 
reason that they form so small an item of the baldpate’s diet. 
ARROW-GRASS FAMILY (JUNCAGINACEAE), 0.36 PER CENT. 
The arrow-grass family was represented in two baldpate stomachs. 
from the State of Washington; both were nearly full of the seeds 
of arrow-grass (T7’riglochin maritima). These plants are quite closely 
related to the pondweeds, but, unlike the pondweeds, their seeds 
are the only parts eaten by birds. 
WATERLILY FAMILY (NYMPHAEACEAE), 0.26 PER CENT; AND HORNWORT FAMILY 
(CERATOPHYLLACEAE), 0.24 PER CENT. 
One stomach from Oregon was nearly filled with 50 of the large 
seeds of spatterdock (Nymphaea sp.) and fragments of many more. 
Two others contained seeds of watershield (Brasenia schrebert), and 
one the seeds of another waterlily (Castalia sp.). 
As already stated, the baldpate seems to lack the gadwall’s taste 
for the foliage of coontail (Ceratophyllum demersum). Only one 
bird (taken in Oregon in December) had its stomach full of this 
plant, and two others had taken a few of the seeds. 
MISCELLANEOUS VEGETABLE FOOD, 7.63 PER CENT. 
The stomach of one baldpate from lower Chesapeake Bay con- 
tained the remains of about 400 seeds of beggar-ticks, or ‘ pitch- 
forks’? (Bidens sp.). In another from Texas were over 500 seeds of 
a wild hehotrope (Heliotropium indicum), which are often taken by 
ducks in much smaller numbers; in this instance they furnished 80 
per cent of the contents. A stomach from Virginia was filled with 
the remains of a great many small tubers of arrowhead (Sagittama 
sp.); one from Massachusetts contained quantities of the leaves of 
pipewort (Hriocaulon sp.); and one from Utah was from a duck which 
had made a meal of the foliage and seeds of picklegrass (Salicornia 
ambigua). Among other items found in small quantities were bits of 
the scales from cones of cypress (Zaxodiuwm distichum), seeds of bur 
