HARDY HYBRID WATER-LILIES. 
293 
they only prevent the roots and rhizomes from meeting, without 
preventing the leaves from intermingling on the surface. Two 
feet down from the bottom of the kerb-stone is enough for the 
depth of the basins. The outside walls ought to be decidedly 
slanted outward, so as to run less risk of their being damaged by 
hard frosts and the pressure of the ice, which would certainly 
happen if they were built straight up. 
A bed of earth six inches deep on the bottom of the basins will 
be amply sufficient for the culture of Water-lilies and for most 
other aquatic plants : it ought to be as free as possible from 
gravel and stones. The best kind of earth is heavyish loam 
from the garden or meadow, but earth composed of leaf-mould 
and alluvial soil is also very suitable. One can also make a 
mixture of them, but it is better not to put with them any fresh 
manure which is still undergoing fermentation. 
As regards the choice of water, that which comes from a 
stream or river is to be preferred, though that from wells will 
do. When the water is taken from running springs it 
ought in summer to be turned off from the basins, so as to keep 
the temperature of the water the same as that of the air; for it 
is essential to remember that Nymplueas thrive best in stagnant 
water, or at least in a very gentle current. 
In stocking a basin w 7 ith Water-lilies the object should be to 
obtain by a harmonious combination and sequence of shades and 
colours a generally dazzling effect, and for that purpose plants 
with high stalks should be avoided, as that would destroy the 
general view. It is necessary also to suppress Conferva and those 
Mosses which are too compact, and certain under-water plants 
which are clogging and clinging, such as Chara, Cabomba, 
Vallisneria. Elodea, Potamogeton, &c., which live at the expense 
of the Water-lilies without adding anything to the ornament of 
the picture. Nevertheless it is as well to except from this pro¬ 
scription Tropas natans and T. verbanensis, Stratiotes aloides, 
and Aponogeton, which are quite worthy of being admitted into 
the society of Water-lilies. 
The Tropas display gracefully upon the surface of the water 
their triangular leaves, with swollen petioles, disposed in rosette¬ 
like form, those of T. verbanensis being larger and particularly 
distinguishable by the stalks and veins of the leaves being of a 
pretty red colour. The fruits of these two annual kinds, known by 
