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.
1. [Cereus giganteus] Engelm. Suwarro.
Leaves 0. Flowers 4′—4½′ long and 2½′ wide, opening from May to July in great numbers near the top of the stem, each surrounded on the lower side by the radial spines of the cluster below it; ovary ovoid, 1′ long, rather shorter than the stout tube of the flower, and covered, like the base of the tube, by the thick imbricated green outer scale-like sepals, with small free triangular acute scarious mucronate tips, furnished in their axils with short tufts of rufous hairs and occasionally with clusters of chartaceous spines, gradually passing into thin oblong-ovate or obovate larger sepals, mucronate or rounded at apex and closely imbricated in many ranks; petals 25—35, obovate-spatulate, obtuse, entire, thick and fleshy, creamy white, ⅔′ long and much reflexed after anthesis; stamens, with linear anthers emarginate at the ends, and filaments united for half their length to the walls of the calyx-tube, those of the exterior rows joined below into a long tube, surrounding the stout columnar style glandular at base and divided at apex into 12—15 green stigmas. Fruit ripening in August, ovoid or slightly obovoid, 2½′ long and 1⅓′ wide, truncate and covered at apex by the depressed pale scar left by the falling of the flower, light red at maturity, separating into 3 or 4 fleshy valves bright red on their inner surface and inclosing the bright scarlet juicy mass of the enlarged funiculi and innumerable seeds; seeds obovoid, rounded, ⅙′ long, lustrous, dark chestnut-brown.
A tree, 50°—60° high, with a trunk sometimes 2° in diameter, thickest below the middle and tapering gradually toward the ends, marked by transverse superficial lines into rings 4′—8′ long, representing the amount of annual longitudinal growth, 8—12-ribbed at base with obtuse ribs 4′—5′ broad, and at summit 18—20-ribbed with obtuse deep compressed ribs, branchless or furnished above the middle with a few, usually 2 or 3, stout alternate or sometimes opposite upright branches shorter but otherwise resembling the principal stem composed of a thick tough green epidermis, a fleshy covering 3′—6′ thick saturated with bitter juice, and a circle of bundles of woody fibres making, with annual layers of exogenous growth, dense tough elastic columns placed opposite the depressions between the ribs, ½′—3′ in diameter and frequently united by branches growing at irregular intervals between them, the woody frame remaining standing after the death of the plant and the decomposition of its fleshy covering. Areolæ pale, elevated, about ½′ in diameter, bearing clusters of stout straight spines with a large dark fulvous base, sulcate or angled, tinged with red, with thick stout spines in the centre of each cluster, the 4 basal horizontal or slightly inclined downward, the lowest being the longest and stoutest and sometimes 1½′ long and 1/12′ thick, the upper shorter, more slender and slightly turned upward, with a row of shorter and thinner radial spines 12—16 in number surrounding the central group. Wood of the columns strong, very light, rather coarse-grained, with numerous conspicuous medullary rays, and light brown tinged with yellow; almost indestructible in contact with the ground, little affected by the atmosphere and largely used for the rafters of houses, for fences, and by Indians for lances, bows, etc. The fruit is consumed in large quantities by Indians.
Distribution. Low rocky hills and dry mesas of the desert; valley of Bill Williams River through central and southern Arizona to the valley of the San Pedro River and to the eastern border of the Colorado Desert between the Needles and Yuma, Yuma County, Arizona, and southward in Sonora.