Capsule

Capsule, a dry, dehiscent, syncarpous, and superior fruit, occurring in many widely-differing groups of flowering plants, and varying considerably in details of structure. It may be one-chambered as in the violets, primroses, and pinks, or many-chambered as in flax, and may have parietal placentation (q.v.) as in violet, central as in flax, or free-central as in primrose. Most capsules split longitudinally into "valves." If this valvular dehiscence takes place down the dorsal sutures or midribs of the carpellary leaves, as in Helianthemum, the rock-rose, it is termed loculicidal, as each loculus or chamber will be broken into, and each valve will consist of two half-carpels. If the splitting be along the ventral sutures, or lines of junction between carpels, it is termed septicidal, and each valve is a carpel. In either of these cases the septa or partitions between the chambers may, as in the thorn-apple, be broken across, when the capsule is called septifragal. Some capsules dehisce by teeth, the carpels only splitting apart slightly at the apex, as in primroses and pinks; others open by small holes or pores, as in the poppy and snapdragon. These last have been separated as pore-capsules; and those which dehisce transversely, forming a round lid, such as Anagallis, the pimpernel, and Lecythis, the monkey-pot, have been termed a pyxidium. There is little to differentiate the siliqua (q.v.) of the Cruciferae from the capsule, and the name is often extended to the inferior capsular fruit, or diplotegia, of Iridaceae, Campanulaceae, etc. In this, however, there is much real difference in development.