18 BULLETIN 465, U. S. DEPARTMENT OF AGRICULTURE. 
A pondweed with abundant tuberous rootstocks (P. heterophyllus^ 
fig. 11) promises to be of exceptional value, since it changes its form 
and continues growth when the water surrounding it lowers or dries 
up. Parts of this plant for propagation are not yet on the market. 
DISTRIBUTION. 
The range of the sago pondweed is from coast to coast as far south 
as Florida. Texas, the Mexican plateau, and Lower California, north 
to Xova Scotia and Hudson Bay. .and along the Pacific coast up to 
latitude 62° north (fig. 19). The distribution of other species has 
been indicated above. 
Fig. IS. — Tubers of sago, pondweed. (Natural size.) B403 
PROPAGATION. 
Sago pondweed is easily transplanted by means of the seeds, which 
are usually gathered with a short section of the top of the plant. 
Growth from seed may be so delicate as to escape notice the first 
season, and yet the pond may be fihed the second season, for the plant 
grows much more luxuriantly after the root system becomes well 
established. Quicker results may be obtained by planting tubers, but 
these are rather difficult to obtain in quantity. Success has recently 
been achieved in transplanting young plants of this species, even 
after shipping them considerable distances. 
Stations of the U. S. Bureau of Fisheries use pondweeds to some 
extent in fish ponds and no difficulty seems to be encountered in 
