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.
2. OPUNTIA Adans.
Trees or usually shrubs, in the arborescent species of the United States with subcylindric or clavate articulate tuberculate branches, covered with small sunken stomata, and containing tubular reticulated woody skeletons, and thick fleshy or fibrous roots. Leaves scale-like, terete, subulate, caducous, bearing in their axils oblong or circular cushion-like areolæ of chaffy or woolly scales terminal on the branches and furnished above the middle with many short slender slightly attached sharp barbed bristles and toward the base with numerous stout barbed spines surrounded in some species, except at apex, by loose papery sheaths. Flowers diurnal, lateral, produced from areolæ on branches of the previous year between the bristles and spines, sessile, cup-shaped; sepals flat, erect, deciduous; corolla rotate; petals obovate, united at base, spreading; stamens shorter than the petals; filaments free or slightly united below; anthers oblong; style cylindric, longer than the stamens, obclavate below, divided at apex into 3—8 elongated or lobulate lobes stigmatic on the inner face. Fruit sometimes proliferous, covered by a thick skin, succulent and often edible, or dry, pyriform, globose or ellipsoid, concave at apex, surmounted by the marcescent tube of the flower, tuberculate, areolate, or rarely glabrous, truncate at base, with a broad umbilicus at apex. Seeds immersed in the pulpy placentas, compressed, discoid, often margined with a bony raphe; testa pale, bony, sometimes marked by a narrow darker marginal commissure; embryo coiled around the copious or scanty albumen; cotyledons large; radicle thin, obtuse.
Opuntia with many species is distributed from southern New England southward in the neighborhood of the coast to the West Indies, and through western North America to Chile, Brazil, and Argentina, the largest number of species occurring near the boundary of the United States and Mexico. Of the species of the United States at least three attain the size and habit of small trees. Cochineal is derived from a scale-insect which feeds on the juices of some of the Mexican species, and the fruit of several species is refreshing and is consumed in considerable quantities in semitropical countries. The large-growing species with flat branches are employed in many countries to form hedges for the protection of gardens and fields; and the branches saturated with watery juice are sometimes stripped of their spines and bristles and fed to cattle.
Opuntia is the classical name of some plant which grew in the neighborhood of the city of Opus in Bœotia.