FIG. 14.--Siliqua or seed-vessel of Wallflower (_Cheiranthus Cheiri_), opening by two valves, which separate from the base upwards, leaving the seeds attached to the dissepiment which is supported by the replum.
From Strasburger's _Lehrbuch der Botanik_, by permission of Gustav Fischer.
FIG. 15.--Capsule of an Orchid (_Xylobium_). v, valve.
FIG. 16.--Seed-vessel of _Anagallisarvensis_, opening by circumscissile dehiscence.
From Strasburger's _Lehrbuch der Botanik_, by permission of Gustav Fischer.
FIG. 17.--Lomentum of _Hedysarum_ which, when ripe, separates transversely into single-seeded portions or mericarps.
FIG. 18.--Fruit of _Geranium pratense_, after splitting.]
Sometimes the axis is prolonged beyond the base of the carpels, as in the mallow and castor-oil plant, the carpels being united to it throughout their length by their faces, and separating from it without opening. In the Umbelliferae the two carpels separate from the lower part of the axis, and remain attached by their apices to a prolongation of it, called a _carpophore_ or _podocarp_, which splits into two (fig. 25) and suspends them; hence the fruit is termed a _cremocarp_, which divides into two _mericarps_. The general term _schizocarp_ is applied to all dry fruits, which break up into two or more one-seeded indehiscent mericarps, as in _Hedysarum_ (fig. 17). In the order Geraniaceae the styles remain attached to a central column, and the mericarps separate from below upwards, before dehiscing by their ventral suture (fig. 18). Carpels which separate one from another in this manner are called _cocci_. They are well seen in the order Euphorbiaceae, where there are usually three such carpels, and the fruit is termed tricoccus. In many of them, as _Hura crepitans_, the cocci separate with great force and elasticity. In many leguminous plants, such as _Ornithopus_, _Hedysarum_ (fig. 17), _Entada_, _Coronilla_ and the gum-arabic plant (_Acacia arabica_), the fruit becomes a schizocarp by the formation of transverse partitions from the folding in of the sides of the pericarp, and distinct separations taking place at these partitions.
Fruits are formed by one flower, or are the product of several flowers combined. In the former case they are either _apocarpous_, of one mature carpel or of several separate free carpels; or _syncarpous_, of several carpels, more or less completely united. When the fruit is composed of the ovaries of several flowers united, it is usual to find the bracts and floral envelopes also joined with them, so as to form one mass; hence such fruits are known as multiple, confluent or _anthocarpous_. The term simple is applied to fruits which are formed by the ovary of a single flower, whether they are composed of one or several carpels, and whether these carpels are separate or combined.
