1. CARICA L.
Short-lived trees, with erect simple or rarely branched stems composed of a thin shell of soft fibrous wood surrounding a large central cavity divided by thin soft cross partitions at the nodes, and covered with thin green or gray bark marked by the ring-like scars of fallen leaf-stalks, and stout soft fleshy roots. Leaves simple, palmately lobed or digitate, crowded toward the top of the stem and branches, large, flaccid, subpeltately palmately nerved, and usually deeply and often compoundly lobed. Flowers regular, monœcious or polygamo-diœcious, white, yellow, or greenish white, in axillary cymose panicles, the staminate elongated, pedunculate, and many-flowered, the pistillate abbreviated and few or usually 3-flowered, generally unisexual and diœcious, occasionally polygamo-diœcious, each flower in the axil of a minute ovate acute bract; calyx minute, 5-lobed, the lobes alternate with the petals; corolla of the staminate flower salverform, gamopetalous, the tube elongated, 5-lobed, the lobes oblong or linear, contorted in the bud; stamens 10; filaments free, those of the outer row alternate with the lobes of the corolla and elongated, the others alternate with them and abbreviated; anthers 2-celled, erect, opening longitudinally, often surmounted by their slightly elongated connective; ovary rudimentary, subulate; pistillate flower, calyx minute, 5-lobed, persistent under the fruit; corolla polypetalous, petals 5, linear-oblong, erect, ultimately spreading above the middle, deciduous; ovary free, sessile, 1-celled or more or less spuriously 5-celled; style 0 or abbreviated; stigmas 5, linear, radiating, dilated and subpalmately lobed at apex; ovules indefinite, inserted in two rows on the placenta, anatropous, long-stalked; micropyle superior; raphe ventral; hermaphrodite flower, corolla gamopetalous, tubular-campanulate, the lobes erect and spreading or subreflexed; stamens 10, in 2 ranks, or 5; ovary obovoid-oblong, longer than the tube of the corolla, more or less spuriously 5-celled below. Fruit slightly 5-lobed, l-celled or more or less completely 5-celled, filled with soft pulp, many-seeded, that produced from the hermaphrodite flower long-stalked, pendulous, usually unsymmetric, gibbous, and smaller than that from the pistillate flower. Seeds ovoid, inclosed in membranaceous silvery white sac-like arils, occasionally germinating within the fruit; seed-coat crustaceous, closely investing the membranaceous inner coat, the outer coat becoming thick, rugose, succulent, and ultimately dry and leathery; embryo in the axis of fleshy albumen; cotyledons ovate, foliaceous, compressed, longer than the terete radicle turned toward the minute pale subbasilar hilum.
Carica with about twenty species is distributed from southern Florida through the West Indies to southern Brazil and Argentina, and from southern Mexico to Chile. One species grows probably indigenously in Florida. The milky juice of Carica contains papain, which has the power of digesting albuminous substances, and the leaves are often used in tropical countries to make meat tender.
The generic name is formed from the Carib name of one of the species.
1. [Carica Papaya] L. Pawpaw.
Leaves ovate or orbicular, deeply parted into 5—7 lobes divided more or less deeply into acute lateral lobes, these secondary divisions entire or rarely lobed, the lowest lobes forming a deep basal sinus, thin, flaccid, yellow-green, 15′—24′ in diameter, with broad flat yellow or orange-colored primary veins radiating from the end of the petiole through the lobes, and small secondary veins extending to the point of the lateral lobes and connected by conspicuous reticulate veinlets; petioles stout, yellow, hollow, enlarged and cordate at base, sometimes becoming 3°—4° in length before the leaves fall. Flowers often beginning to appear on plants only 3° or 4° high and a few months old, produced continuously throughout the year, the staminate in clusters on slender spreading or pendulous peduncles 4′—12′ long, the pistillate in 1—3-flowered short-stalked cymes; staminate flowers fragrant, filled with nectar, their corolla ¾′—1¼′ long, with a slender tube and acute lobes; anthers oblong, orange-colored, surmounted by the rounded thickened end of the connective, those of the inner row almost sessile and one third larger than those of the outer row, shorter than their flattened filaments covered, like the connectives, with long slender white hairs; pistillate flowers about 1′ long, with erect petals, without staminodia; ovary ovoid, ivory-white, slightly and obtusely 5-angled, 1-celled, and narrowed into a short slender style crowned by a pale green stigma divided to the base into 5 radiating lobes dilated and 3-nerved at apex. Fruits hanging close together against the stem at the base of the leaf-stalk, obovoid to ellipsoid, and obtusely short-pointed, yellowish green to bright orange color; in southern Florida not more than 4′ long and 3′ thick, and usually smaller, with a thick skin closely adherent to the sweet insipid flesh forming a thin layer outside the central cavity; seeds full and rounded, about 3/16′ long; outer portion of the seed-coat rugose at first when the fruit is fully grown but still green, ivory-white, very succulent, and usually separable from the smooth paler chestnut-brown lustrous interior portion, the outer part turning black as the fruit ripens and becoming adherent to the inner portion closely investing the thin lustrous light red-brown inner coat.
A short-lived tree, in Florida attaining a height of 12°—15°, with a trunk seldom more than 6′ in diameter; in the West Indies and other tropical countries often twice as large, with a trunk occasionally dividing into a number of stout upright branches. Bark thin, light green, becoming gray toward the base of the stem.
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.