RIVER GARDENS; 
not only for its graceful appearance, but also as 
one of the most effectual of vegetable aerators. 
The Valisneria has the same valuable pro¬ 
perty, and its grass-like foliage is, at the same 
time, one of the most graceful adjuncts to an 
Aquarium, as shown in Plate VI., in which it is 
supposed to be a central object, round which gold 
fish are sporting in the enjoyment of the grateful 
shade it affords. The Valisneria and Anacharis 
have a pretty effect grown together, and are the 
only plants (attended by a few fresh-water mollusca) 
necessary to an Aquarium in which a few choice fish 
only are kept. Valisneria is named after the Italian 
naturalist Valisnei, who wrote on insects and plants 
in the last century. 
The Water Lily tribe have been described in 
another place, as also the ornamental Water Grasses, 
and we now come, therefore, to a series of water 
plants of a lower range in the scale of vegetation, 
though not less curious and interesting. 
These consist of a class of fresli-water vegeta¬ 
tion analogous to the sea-weeds of our coasts, and 
also of another family, consisting of two genera 
of plants only, Nitella and Chara. These two 
genera contain, however, some pretty vegetable 
forms. The Flexile nitella may be known by the 
40 
