
AQUATIC. PLANTS OF FRESHWATER 

In the natural state Vallisneria usually dies down to the tuft in the 
cold winter season, but in the aquarium it may thrive the entire year 
and is a very graceful and ornamental plant and an excellent oxygenator. 
[t may be distinguished from the ribbon Sagittarias by the narrower and 
more uniform width of the leaves, their usually rounder and more blunt 
tips, their thinner, more distinctly nerved and veined appearance and the 
more sharply defined midribs; also the distinct close nerves at both edges 
of the leaf and the absence of the cellular structure, which is very marked 
in the leaves of Sagittaria. In the aquarium it should be planted deeply 
and the runners kept well under the pebbles or sand. The young spring 
growth is most likely to survive and become acclimated to household 
conditions. 
A cultivated variety, /. spiralis gigantea (Hort.) recently developed, 
has % inch broad and 1 to 3 feet long leaves. It grows better in aquarium 
conditions than the common native form, and may be had of florists 
who propagate aquatic plants. 
MYRIOPHYLLUM AND PROSERPINACA 
These aquatic plants are of the same family, the former very hardy 
and common to most ponds and still water in the United States, and two 
species of the latter native in eastern North America. The botanical 
designation of Myriophyllum is from the Greek and means ten-thousand- 
leaved, the common English names being Water-milfoil or Spikewort. 
It is a genus containing 15 to 20 species found from the frigid zone to 
the tropics, of which the three forms hereafter described may be found in 
water courses or procured of dealers, but any of those mentioned may be 
introduced into the aquarium. It is a fairly good oxygenator but does 
not always keep in full foliage indoors. All have pinnate submerged 
leaves finely divided into threadlike segments, in whorls about a weak 
stem, and entire or serrate floral leaves. The species indigenous to the 
United States and to North America are:—M. spicatum, Spiked Water-mil- 
foil; M. verticillatum, Whorled Water-milfoil; M. alternifolia, Loose- 
flowered Water-milfoil; M@. tenel/lum, Slender Water-milfoil; M. Aumile, 
Low Water-milfoil; MM. heterophyllum, Various-leaved Water-milfoil; M. 
pinnatum, Pinnate Water-milfoil; and M. farwellii, Farwell’s Water-milfoil; 
with the so-called Proserpinaca or Parrot’s Feather as an additional species 
of the same genus. 
Myriophyllum spicatum (Linn.) or Spiked Water-milfoil, Fig. 115, is 
the most generally distributed, and native from Newfoundland, Manitoba 
and the Northwestern Territory to Florida on the Atlantic slope, and 
Iowa, Utah and California. The submerged leaves are finely dissected 
into capillary divisions and grow in whorls of 4’s and 5’s; the small floral 
leaves ovate, entire or serrate, usually shorter than the flowers. The flowers 
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