Distribution. Florida from the southern shores of Bay Biscayne on the west coast and of Indian River on the east coast to the southern keys, growing sparingly in rich hummocks; common in all the West Indian islands, in southern Mexico, and in the tropical countries of South America; now naturalized in most of the warm regions of the world, where it is universally cultivated for its fruit, which is considered one of the most wholesome of all tropical fruits, and has been much improved by selection.
XLV. CACTACEÆ.
Succulent trees or shrubs, with copious watery juice, numerous spines springing from cushions of small bristles (areolæ), and minute caducous alternate leaves, or leafless. Flowers large and showy, perfect, usually solitary; calyx of numerous spirally imbricated sepals forming a tube, those of the inner series petal-like; corolla of numerous imbricated petals, in many series; stamens inserted on the tube of the calyx, very numerous, in several series, with slender filaments and introrse 2-celled oblong anthers, the cells opening longitudinally; pistil of several united carpels; ovary 1-celled, with several parietal placentas; styles united, terminal; stigmas as many as the placentas; ovules numerous, horizontal, anatropous. Fruit a fleshy berry. Seeds numerous, with albumen; cotyledons foliaceous; radicle turned toward the hilum.
The Cactus family with twenty genera and a very large number of species is most abundant in the dry region adjacent to the boundary of the United States and Mexico, with a few species ranging northward to the northern United States and southward to the West Indian islands, Brazil, Peru, Chile and the Galapagos Islands. Two of the genera have arborescent representatives in the flora of the United States.
CONSPECTUS OF THE ARBORESCENT GENERA OF THE UNITED STATES.
Branches and stems columnar, ribbed, continuous; leaves 0; flower-bearing and spine-bearing areolæ distinct; flowers close above spine-bearing areolæ; tube of the flower elongated; seeds dark-colored.1. [Cereus.] Branches jointed, tuberculate; leaves scale-like; flower-bearing and spine-bearing areolæ not distinct; tube of the flower short and cup-shaped; seeds pale.2. [Opuntia.]
1. CEREUS Haw.
Trees or shrubs, with columnar ribbed stems, and buds on the back of the ridges from the axils of latent leaves, geminate, superposed, the upper producing a branch or flower, the lower arrested and developed into a cluster of spines surrounded by an elevated cushion or areola of chaffy tomentose scales. Flowers lateral, elongated, the calyx-lobes forming an elongated tube, those of the outer ranks adnate to the ovary, scale-like, only their tips free, those of the inner ranks free, elongated; petals cohering by their base with the top of the calyx-tube, larger than its interior lobes, spreading, recurved; stamens numerous; filaments adnate by their base to the tube of the calyx, those of the interior ranks free, the exterior united into a tube; style filiform, divided into numerous radiating linear branches stigmatic on the inner face; stalks of the ovules long and slender, becoming thick and juicy in the fruit. Seeds with very thin albumen; embryo straight; cotyledons abbreviated, hooked at apex; radicle conic.
Cereus with at least two hundred species inhabits the dry southwestern region of North America, the West Indies, tropical South America, and the Galapagos Islands. Of the numerous species found within the territory of the United States only one assumes the habit and size of a tree. The fruit of several species is edible, and the ribs of the durable woody frames of the stems of the large arborescent species are used for the rafters of houses and for fuel. Many of the species are planted in warm dry countries in hedges to protect cultivated fields, and others are popular garden plants valued for their beautiful flowers, which are sometimes nocturnal and exceedingly fragrant.
The generic name relates to the candle-like form of the stem of some of the species.