Asarum canadense, the Wild Ginger of North America, has kidney-shaped leaves, and dark purplish brown flowers, on very short footstalks, which resemble those of the genus Stapelia, both in appearance and smell.
ORDER CLXVI.—CYTINEÆ.
The most interesting plant in this order is Nepenthes distillatoria, the Chinese Pitcher-plant, the leaves of which have a tendril at the point curiously dilated at the extremity, so as to form a cup-like appendage, which is generally full of water. The rim of the pitcher is beautifully ribbed, and it is furnished with a lid. The male and female flowers are on different plants, but neither of them possess much beauty. The remarkable Javanese fungus Rafflesia belongs to this order.
A small order called Cephaloteæ, and containing only the genus Cephalotis, formerly included in Rosaceæ, is introduced here.
ORDER CLXVII.—EUPHORBIACEÆ.
| Fig. 144.—Euphorbia. | Fig. 145.—Fruit of Euphorbia. |
The genus Euphorbia is well known by the British weed called Caper Spurge, and the showy stove plants which belong to it. The male and female flowers are distinct; but both are inclosed in one cup-like involucre. In fig. 144, a is the involucre, b the female flower, and c the male ones. The fruit (fig. 145) consists of three carpels, each containing a single seed, which divide with elasticity when the seeds are ripe. All the plants belonging to this order have a milky, glutinous juice when young, which in some genera becomes solid when exposed to the air. This is particularly the case with Siphonia Hevea, a Brazilian tree, the sap of which yields the Indian rubber used for Macintosh cloaks, &c.; it being more suitable for that purpose than the caoutchouc yielded by the Ficus elastica, which is the true Indian Rubber. The principal other genera belonging to this order are the Box (Buxus), the tree kind of which yields the wood used for wood-engraving, and the dwarf variety is employed as edging for gardens; Croton, an annual species of which (Croton Tiglium) yields the celebrated Croton oil; the Cassava (Jatropha Manihot), which though poisonous in a raw state, becomes the wholesome food called tapioca, when properly prepared; Palma Christi (Ricinis communis), from the seeds of which castor-oil is made; and the Manchineel tree (Hippomane), which is said to be so poisonous as to occasion the death of those who sleep beneath its shade.