Fig. 139.—Snowdrop tree (Halesia tetraptera).to three seeds. The seeds have two skins, the inner one like a cobweb, and the outer one spongy. The bark, when wounded, affords the gum called storax. Halesia has drooping bell-shaped white flowers, something like those of the Snowdrop, (see a in fig. 139,) with four petals and twelve or sixteen stamens combined into a tube at the base. The fruit is a dry, winged drupe, which has four angles in H. tetraptera (b), and two in H. diptera; and which contains a stone or putamen (c), which has two or four cells, and as many seeds. Some botanists make Halesiaceæ a separate order.
ORDER CXX.—MYRSINEÆ.
Showy shrubs, with evergreen leaves, and cymes of white or red flowers, which require a stove or greenhouse in England. The plants belonging to this order may be easily known on cutting open their flowers, as they are the only monopetalous flowers among the stove plants that have the stamens opposite the lobes of the corolla; the general position of the stamens being between the lobes. The principal genera in this order are Myrsine, the species of which are greenhouse shrubs; and Ardisia, the latter being well-known stove shrubs, with white flowers and red berries. Theophrasta, Clavija, and Jacquinia, were included in this order; but they are now formed into a new one, under the name of Theophrasteæ.
ORDER CXXI.—SAPOTEÆ.
This order is best known by the genera Argania, Sideroxylon, Chrysophyllum, and Bumelia, all of which are stove or greenhouse plants. The seeds of Achras Sapota contain abundance of oil, which is so concrete as to have the appearance of butter; and hence the tree is called the Butter-tree. Sideroxylon has such hard wood as to be called the Iron-tree. The juice of all these plants is milky, and the milk is wholesome as food.
ORDER CXXII.—EBENACEÆ.