Cactus
(from Kaktos, a name used by Theophrastus to describe a spiny plant). This generic term is popularly applied to all members of the extensive family Cacteae, which order may be distinguished by the following characteristics: Calyx composed of many sepals, usually indefinite in number, the inner series not readily distinguishable from the petals, united and adnate a great length to the ovary; with the tube smooth in the genera Mammillaria, Melocactus, and Rhipsalis; or with the lobes of the sepals crowning the fruit, and having the tube scaly, as in the genera Cereus, Opuntia, and Pereskia. Petals disposed in two or more series, hardly distinguishable from the inner sepals, and somewhat united to them; sometimes irregular, and disposed in a long tube at the base, but distinct at the apex, as in the genera Mammillaria, Melocactus, and Cereus; sometimes equal and distinct to the very base, forming a rotate corolla, as in the genera Opuntia, Pereskia, and Rhipsalis. Stamens indefinite, disposed in many series, more or less cohering with the petals or inner sepals; filaments slender, filiform anthers ovate, versatile, two-celled. Ovarium obovate, fleshy, one-celled. Fruit fleshy, one-celled, many seeded, either smooth and crowned by the calyx, or covered with scales, scars, or tubercles, and umbilicate at the apex. This order contains fleshy or succulent shrubs, very variable in habit and size. Flowers very variable, showy, or minute, usually solitary, sessile, rarely in fascicles, ephemeral, expanding by night or day. Leaves usually wanting, but, when present, small, caducous, and terete, rarely flat and expanded, sometimes alternate and disposed in a spiral order, always glabrous and fleshy. Prickles or bristles disposed in fascicles, rising from the axils of the leaves. In the leafless genera, the fascicles of spines are disposed on the angles of the stem, rising from tubercles. Stems usually angular, winged, or regularly beset with tubercles, rarely terete, usually jointed; joints compressed. A group of Cacti is shown at Fig. 312, for which we are indebted to Herr Fr. Ad. Haage, jun., of Erfurt, Germany. See Cereus, Disocactus, Echinocactus, Epiphyllum, Leuchtenbergia, Mammillaria, Melocactus, Nopalea, Opuntia, Pelecyphora, Pereskia, Phyllocactus, and Rhipsalis.