THE WHITE WATER-LILY— continued. 
air-vessels. An incomplete dissection led to the embryo-sac in Water-lilies being 
mistaken for a single cotyledon, so that these characters, together with the lily-like 
texture of their flowers to which they owe their name, suggested that the Family 
might be monocotyledonous. 
The genus for which Linn6 adopted the name Nymph^a from Theophrastus, or 
rather the chief part of it, was named by Richard Antony Salisbury Castalia^ with an 
allusion as Classical as the earlier name. It has a stout, starchy rhizome which has 
been used for food. In this is stored the food-reserve manufactured by the floating 
leaves which has all to travel from the surface of the water to the bottom and back 
again to the flower, fruit, and seeds. The circular leathery leaves are cordate at the 
base and have their stomata on the upper surface, which is protected by a coating of 
wax from being wetted. The under side of the leaves is often red or purple from 
the presence of anthocyan, a colouring-matter which converts light rays into heat 
and thus assists in the chemical processes or metabolism in the leaf. The young 
leaves rise erect from the water with their two sides rolled inwards like scrolls, and 
as these unroll they fall flat upon the water. 
The floating blossoms are, of course, out of reach of crawling insects, and 
their fragrance attracts flies and beetles. They are open from about seven in the 
morning to four o’clock in the afternoon ; and if not pollinated on the day of their 
first expansion they close and sometimes sink slightly, only to re-expand on one or 
more succeeding days. As Tom Moore well put it — 
“ Those virgin lilies all the night 
Bathing their beauties in the lake, 
That they may rise more fresh and bright 
When their beloved sun's av^^ake." 
Their four outer perianth-leaves in our British species (N. alba Linne) are green 
externally. Though usually regarded as a calyx, they have been explained as a 
bract with both margins outside, two lateral bracteoles, and one sepal with both 
margins inside the bracteoles. There are four outer petals alternating with the 
so-called sepals, four inner ones alternating in turn with the outer ones, and these 
eight form the starting-points of eight spiral series, generally of four petals each, the 
inner ones narrowing. Then follow from fifty to a hundred spirally-arranged 
stamens with white petaloid filaments and long linear yellow anthers, which bend 
over the stigma and, when insect visits fail, ensure self-pollination. In the centre 
of the flower from fifteen to twenty carpels are imbedded in the fleshy disk and 
form the globular fruit which ripens under water. As each seed is surrounded by a 
spongy aril which becomes mucilaginous, and bubbles of air are imprisoned between 
the aril and the seed ; when the fruit rots, the seeds float to the surface, are carried 
down stream, and, as the air escapes, sink to the mud below. 
t 
