10 AQUATIC PLANTS IN POND CULTURE. 
species. It makes an ideal growth and affords abundant cover for 
the fish and for the minute life upon which the fish feed, and is appar- 
, 
Fic. 1.—Spiked water-milfoil (My- 
riophyllum spicatum). Found in 
deep water, Newfoundland to 
Manitoba and the Northwest Ter- 
ritory, south to Florida, Iowa, 
Utah, and California. (After 
Britton & Brown.) 
Commonly known as fox-tail. 
ently a good oxygenator. At the same 
time it offers but little obstruction to — 
seining operations, owing to its slender 
feathery growth. Even for ponds hav- 
ing rich muck bottom it has been found 
most satisfactory, though here consid- 
erable work is required to remove it 
when preparing for seining. 
For ponds with sterile bottoms of 
clay, sand, or gravel, where fox-tail 
will not thrive, parrot-feather (Jyre- 
ophyllum proserpinacoides) attains an 
excellent growth and affords abundant 
lodgment for minute aquatic life and 
for the alevins; it also provides a sufli- 
cient amount of shade for the brood fish 
and suitable cover for their nesting 
places. Large-mouth black bass seem 
to prefer the fibrous roots of these 
plants to all other nesting materials. Both plants disappear from 
the warmest parts of the ponds by midsummer and are replanted in 
the fall or following spring. 
Near 
the inflow, especially of ponds which 
are abundantly supplied with water, 
the plants thrive throughout the year. 
The parrot-feather is more suscepti- 
ble to high temperatures than the 
fox-tail. These two plants have 
proved so satisfactory at Cold 
Springs that the. superintendent has 
seen little occasion to experiment 
with other species. 
FISH LAKES, WASHINGTON, D. C. 
Although the Fish Lakes at Wash- 
ington are no longer maintained, 
observations upon the characteristics 
of the plant life are valuable for 
purposes of comparison. The bot- 
toms of the ponds were of dark fer- 
Fig. 2.—Chilean 
(My- 
(After 
Britton & Brown.) Native of Chile, 
introduced in various localities in 
the United States, where it is 
known chiefly as ‘‘ parrot-feather.” 
water-milfoil 
riophyllum proserpinacoides). 
tile soil, the maximum water temperature was about 87° F., and 
the plant growth was extremely dense. Whether the elimination 
