ORDER IX. NYMPHÆACEÆ.—THE WATER-LILY TRIBE.
Fig. 110.—The flower, leaf, and seed-vessel of the White Water-lily, greatly reduced in size.
The principal genera in this order are Nymphæa, Euryale, Victoria, Nuphar, and Nelumbium. The flowers of the common White Water-lily (Nymphæa alba) consist of numerous sepals, petals, and stamens, all of which might be mistaken for petals, being principally distinguished by their colour. The sepals, (a in fig. 110,) are green on the outside, but they are white within, and of the same fleshy substance as the petals (b). The stamens (c) look like narrow yellow petals; they are pointed, and bear the pollen in two lobes near the point, which open longitudinally when ripe. The inner row of stamens are without anthers, and form a kind of vandyke edging to the pistil, as shown at e. The pistil consists generally of sixteen carpels, growing together into a vase-like, many-celled berry, as shown at d; the spreading stigmas, which have also grown together, forming a kind of lid. The carpels are completely enclosed by the receptacle which rises up round them, and forms a thick fleshy covering, as shown at f. The seeds are numerous, and they are covered with a thick leathery skin. The embryo is small, and it is surrounded by a great mass of floury albumen. The leaves (g) are large and nearly round; and the main root, which is called a rhizoma, is thick and fleshy, and is, indeed, an underground stem. There are several kinds of Nymphæa, the most remarkable of which is the Egyptian Lotos (N. Lotos), the flowers of which are white tinged with pink; and both the roots and seeds of which are eaten. Euryale is a genus of South American Water-lilies, generally with small flowers, and large rough leaves; and Victoria regina, also a native of South America, is perhaps the most magnificent Water-lily in the world; the leaf, which is peltate and turned up at the brim, being of a deep crimson on its lower surface, is upwards of six feet in diameter; and the flowers are more than a foot in diameter, with a corolla of more than a hundred large white petals tinged with pink.
The genus Nuphar consists of only three or four species, the most common of which is N. lutea, the common yellow Water-lily, a native of Britain. The flower has a cup-shaped calyx of five large yellow sepals, the tips of which curve inwards. The petals are small, truncate, and flat, with a small pore on the back of each; and the stamens, which are very numerous, have broad petal-like filaments. They differ, however, very much in appearance from those of the genus Nymphæa, and they are differently placed, springing from the base of the vase-like pistil, and not from the upper part. There are from sixteen to twenty carpels enclosed in the dilated receptacle, to which the stigmas form a ray-like cover; and each carpel contains several seeds. The leaves are somewhat cordate, and rise rather above the surface of the water, and the rhizoma, or root-stem, is very thick. The common yellow Water-lily, or Brandy-bottle, as it is sometimes called from the smell of its flowers, is common in every part of England, and it is generally found in small ponds or ditches. The other species are mostly natives of North America.
The Indian Lotos (Nelumbium speciosum) differs so much from both the preceding genera, as to be considered by some botanists to form a different natural order. The sepals and petals are so intermingled in the flower as to be scarcely distinguishable; but the filaments of the stamens are less broad and petal-like. The disk is still elevated, but it has lost the vase-like form, and it appears as though the top had been abruptly cut off; while the carpels are no longer joined together, but are plunged each separately in the fleshy receptacle, or torus, with their stigmas quite distinct. As the carpels are only half immersed in the torus, and thus show their styles and stigmas, they have a very singular and bottle-like appearance; and the torus, when they are taken out of it, looks like a piece of honey-comb. The rhizoma is white and fleshy. The stalks of the flowers and leaves rise considerably above the water; and thus the flowers have not the graceful appearance of those of the Nymphæa, which seem to repose on the surface. The leaf is very large, being sometimes one or two feet in diameter; and it is always peltate, with the stalk exactly in the centre. There is only one seed in each carpel of the Nelumbium; and this seed, which has no thick leathery skin, is of about the size and shape of an acorn. It is very good to eat, having a sweet milky flavour, and in botanical construction it resembles the common bean, having no albumen, but a very large embryo. This is probably the reason why it has been supposed to be the bean of Pythagoras, and why it is called the Sacred Bean of India. One of the Hindoo fables represents the god Bramah as first appearing in the form of a child, cradled on a Lotos leaf, and floating on the waste of waters.
There are several kinds of Nelumbium, one of which, a native of America, has double yellow flowers; and they all require a stove in England.