Order IX. Palmae, Juss.—The Palm Tribe.
Flowers with a proper, often coralline perianth, usually hermaphrodite.
1. Leaves with parallel veins, either proceeding from the base to the apex (straight-veined), or curved and proceeding from the midrib to the margin (curved-veined).
Flowers sessile on a branched scaly spadix, usually unisexual.
Characters.—Flowers hermaphrodite, or frequently polygamous. Perianth six-parted, in two series, persistent; the three outer segments often smaller, the inner sometimes deeply connate. Stamens inserted into the base of the perianth, usually definite in number, opposite the segments of the perianth, to which they are equal in number, seldom three; sometimes, in a few polygamous genera, indefinite in number. Ovary one, three-celled, or deeply three-lobed; the lobes or cells one-seeded, with an erect ovule, rarely one-seeded. Fruit baccate or drupaceous, with fibrous flesh. Albumen cartilaginous, and either ruminate or furnished with a central or ventral cavity; embryo lodged in a particular cavity of the albumen, usually at a distance from the hilum, dorsal, and indicated by a little nipple, taper or pulley-shaped; plumule included, scarcely visible; the cotyledonous extremity becoming thickened in germination, and either filling up a pre-existing cavity, or one formed by the liquefaction of the albumen in the centre.—Trunk arborescent, simple, occasionally shrubby and branched, rough, with the dilated half-sheathing bases of the leaves or their scars. Leaves clustered, terminal, very large, pinnate, or flabelliform, plaited in vernation. Spadix terminal, often branched, enclosed in a one or many-valved spathe. Flowers small, with bractlets. Fruit occasionally very large. (R. Brown, 1810.)
Properties.—Palms, considered in a dietetical and medicinal point of view, are of the highest importance to the inhabitants of tropical regions. Their stems yield starch (sago) sugar, and wax; their terminal leaf buds are boiled and eaten as a kind of cabbage; their fruits yield oil, sugar, and resins; and their seeds form articles of food, and yield, by pressure, fixed oil.
In the abundance of sugar and starch which the palms yield, this family resembles the grasses. But they are distinguished from the latter in containing, in some cases, a large quantity of fixed oil. To these three principles are chiefly due the nutritive qualities of palms. But these substances being non-nitrogenized, are merely fat-making and heat-yielding, and without the addition of proteine compounds (found in the seeds, and probably in other edible parts of palms), would be insufficient to support life.
Palm sugar, in the crude state, is called jaggary. By fermentation, it yields toddy or palm wine, from which, by distillation, an ardent spirit (arrack or rack) is obtained. Date sugar, and also other kinds of palm sugar, are imported into England, and are used by grocers for mixing; but, being deficient in what in trade is called "strength," they do not pay for refining. [Pharmaceutical Journal, vol. v. p. 61, 1845.]
Wax, astringent matter (tannin), and resinous principles, are useful products obtained from palms, but they are of less frequent occurrence than the substances before mentioned. Still less frequently met with are acrid principles.
The ashes obtained by the combustion of palm leaves yield potash.
1. Palmae Fariniferae.—Sago Palms.
The trunk of old trees of Caryota urens, called, by Robinson, [A Descriptive Account of Assam, p. 56, Calcutta, 1811.] the Sago palm of Assam, yields a sago which both Roxburgh [Flora Indica, vol. iii. p. 626.] and Robinson consider to be very little if at all inferior to the sago of the Malay countries. From Phoenix farinifera, which grows in the Coromandel coast, is likewise obtained a sago, but which is less nutritious and palatable than the common sago. [Ibid., p. 786.] Corypha umbraculifera, or the Talipat palm, yields sago in Ceylon; which would appear from the statement of Bennett [Ceylon, and its Capabilities, p. 95, Lond. 1813.] to be of inferior quality.
Japan Sago is said to be obtained from several species of Cycas. None of this, however, reaches England. (See order Cycadeae.)
2. Palmae oleiferae.—Oil Palms.
Oil is obtained from the fruit of some, and from the seeds of many palms. Two oils obtained from palms are found in commerce: they are palm oil and cocoa-nut oil; the one obtained from a species of Elaeis, the other from a Cocos.
3. Palmae ceriferae.—Wax-bearing Palms.
The only palm wax which has been brought to Europe as an article of commerce is the produce of the following palm:—
Corypha cerifera, Mart., Gen. et Sp. Palm. tab. 49 and 50; Caranaiba, and Ananachi cariri, Piso et Marcgrave, pp. 62 and 130, 1648; Carnauba, Brande, Phil. Trans. 1811, and Virey, Journ. de Pharm, t. xx. p. 112, 1834.
—Grows on the shores of the Rio Francesco, in the Brazils. [The stems of this palm are sold at Haynes's timber-yard, Long Lane, Smithfield, London, under the name of Palm Wood.]
In the axillae of the leaves, waxy scales are secreted, which are collected and melted by the Indians. The wax thus obtained is imported into this country from Rio Janeiro under the names of Carnauba Wax, Brazilian Wax, or Palm Wax. It was submitted to chemical examination by Mr. Brande, and has subsequently been analyzed by Lewy, who found it to consist of C36H35O2. The fusing point of this wax is 180° F. It is, therefore, less fusible than bees' wax, whose melting point is about 150° F. Being a genuine wax, it is applicable to some of the purposes for which common bees' wax is now employed.
4. Palmae resiniferae.—Resin-bearing Palms.
The only resinous substance used in medicine and the arts, and which is obtained from the palms, is Dragon's blood, the produce of Calamus Draco.
5. Palmae Tanniniferae.—Tannin-bearing Palms.
The only palm which yields any officinal astringent substance is the Areca Catechu.