
AQUATIC PLANTS OF FRESHWATER 

in smaller groups of two or three stalks, to prevent sloughing-off at the 
constricted binding. 
VALLISNERIA 
This aquatic plant, found in freshwater all over the world, is an 
excellent aquarium aerator, belonging to the order of Vallisneriacee, 
named for Vallisneri, the Italian naturalist, and is a genus of but one 
universally distributed species, the Vallisneria spiralis, Kel or Tape-Grass, 
also known as Wild Celery, due to its imparting a celerylike flavor to wild 
fowl. 
Vallisneria spiralis (Linn.) Fig. 114, 1s a hardy plant with linear or 
strap-shaped five-nerved leaves of the same breadth their entire length 
and 1 to 6 feet long, dependent upon the depth of water, arranged in 
fascicles at the end of the creeping stems 
and attached to the mud or sand by root- 
fibres. In the axils of these leaves, buds 
are produced which constitute the starting 
points not only of new shoots growing 
parrallel to the bottom and developing 
foliage buds at the extremities, but of 
others which grow upward. Shoots are 
also developed terminating in a kind of 
bladder composed of two concave bracts 
overlapping each other, within which the 
flowers are enclosed. Of the individual 
plants some develop pistillate or female 
flowers only and others staminate or male 
flowers, both small and inconspicuous. 
The female flowers develop on very long 
spiral scapes and split when the stigmas 
have reached the pollen-receiving stage and 
the flowers are thrust above the water. 

The male flowers are borne on short stalks 
near the bottom; which, when fully de- 
veloped, break away from their stalks, rise 
to the surface, and as they float about 
convey the pollen to the female flowers 
and so fertilize them; after which the long 
flower stalks twist themselves into tight 
spirals and draw the flowers below the 

‘ F FIG. 114. Eel Grass, Vallisneria spiralis. 
surface, there to ripen the fruit. Male and female plants. | Reduced one-half. 
188 
