Pallenis
(from palea, chaff; in allusion to the chaffy receptacle). SYNS. Asteriscus, Athalmus. ORD. Compositae. A monotypic genus. The species is a soft, sub-silky, villous, hardy, annual herb. For culture, see Buphthalmum. P. spinosa (spiny). fl.-heads yellow, mediocre or rather large, solitary at the tips of the branches; achenes glabrous or slightly pilose; involucre hemispherical; receptacle slightly convex. July. l. obovate-or oblong-lanceolate, alternate, entire; floral ones, or outer involucral bracts, leafy, often pungently mucronate. h. 2 1/2ft. Orient, South Europe, and North Africa, 1570. (S. F. G. 898, under name of Buphthalmum spinosum.) PALMAE, or PALMACEAE. This large order is pre-eminent, not only among monocotyledons, but in the whole world of plants, for the grandeur and beauty attained by many of the species. The order is also pre-eminently tropical in its distribution, so that, to dwellers in the cooler temperate zones, its wonderful beauty is a thing to be read of, not to be realised. Palms under glass, however spacious the accommodation allowed them, fail to impress the mind as do the same subjects in their native forests. Those who have had the pleasure of seeing these "Princes of the Vegetable Kingdom," as Linnaeus rightly styled them, in their native wilds, must feel that the impressions produced can never be effaced from the memory. While some tower, when full grown, to a height much surpassing 100ft., without emitting a leaf (e.g., Ceroxyloz andicola), the stems of others do not exceed 2ft. or 3ft. in length, and 1/4in. in thickness; others, again, have the stems so short that the leaves borne on the top of the stem rise out of the soil, and the whole plant does not exceed 3ft. in height. These dwarf Palms, however, are no less graceful than their lofty allies, and are, moreover, better known than the latter in European greenhouses, for which their dwarf stature so well fits them.
The stem is usually unbranched from the ground to the top, but in the Hyphaene thebaica it bifurcatcz several times, and it also does so in a few others. Once formed, the trunk of a Palm increases in height, but not in thickness, and it tapers upwards almost from the base. In most, the stems rise erect, or are only slightly curved; but in certain weak-stemmed genera, the stems lie on the soil, or twine among the branches of adjacent trees for support (e.g., Calamus, Desmoncus, &c.). The outer surface of the trunk in Palms is usually very hard, while the centre is soft, and consists of a mass of thin-walled cells, amid which run the woody bundles. The central mass can be easily removed, leaving a hollow tube. The leaves vary no less than the stems; but they belong to two leading forms, viz., the feather-veined, in which the chief veins of the leaf-blade arise from the sides of a long midrib (see Fig. 9), and the fan-veined, in which the midrib is so short that, at first sight, the veins all seem to arise from the top of the leaf-stalk, and to spread out like the ribs of a fan through the leaf-blade (see Fig. 10). In both forms, the blade may be undivided, except at the end, where there are always two lobes, separated by a division down to the midrib; or it may be divided partially, or down to the midrib along each side, and these segments, or pinnae, may be few (as in Fig. 11) or many (see Fig. 9), and they may themselves be divided into smaller segments, as in Caryota (see Fig. 12). In length, the leaves vary between less than 1ft. (e.g., in species of Malortiea) and a total of nearly 40ft. (as in the leaves of young plants of Maximiliana regia). The undivided lamina may, in a few species, reach a size of nearly 30ft. long by 5ft. broad (e.g., in Manicaria saccifera). The leaves in the very young plants of almost all species of Palms are undivided, except at the tip, and the species are remarkably alike, in most cases, while young.
The inflorescence assumes the form of a spadix, simple or branched, and frequently very much branched. The forms shown in Figs. 11 and 12 are of frequent occurrence. The spadix is inclosed in spathes, usually two in number; the outer, or lower, is short, and open at the tip; the inner is usually much larger, sometimes several feet long, woody or leathery, and, for a considerable time, entirely incloses the spadix. In some genera, there are from three to six spathes, only the inner of which is complete; and, in the tribe Calameae, the spathes are replaced by a large number of short, tubular, incomplete spathellae, ranged all along the peduncle and branches. The spadix always bears numerous inconspicuous flowers, which, in by far the greater number of species, are unisexual, not often hermaphrodite. Individual plants, or individual spadices in many species, are either male or female; but, in most, the same spadix bears flowers of both sexes, the females usually lower down, the males nearer the tips of the branches; or they may be associated in various ways, e.g., in Cocoinae, Geonoma, &c.; there is frequently a male flower at each side of a female, so that they stand in groups of three. They are often sunk in pits in the fleshy spadix, or they may be stalked; the flowers are almost always quite regular in structure. Frequently, the abortive male organs are found in female flowers, and vice versa. The stamens are usually six, but vary from three to very many. The ovary is typically composed of three carpels, rarely of more; but, usually, only one grows to ripeness, and only the remains of the others are left in the ripe fruits. These vary greatly. In certain groups, they resemble berries; in others, they are more like drupes, with a hard inner layer, or endocarp, as in the well-known Cocoa-nut and the Coquillanut, so often used for carved ornaments. The outer coat of the fruit is usually thin, leathery or dry, and smooth, or only bears prickles; but, in Calameae, it is covered with scales, arranged in spirals. The middle layer of the fruit (mesocarp) is usually traversed by woody bundles, which, in some, are extremely abundant, and, in others, rather few and ill-developed. In the Cocoanut, this layer is very thick and fibrous, and, from it, "coir," or fibre, for ropes, matting, &c., is prepared. In many Palms, the mesocarp contains oil in considerable quantity. The fruits of the "Oil Palm" (Elaeis guineensis) yield so much that they form a valuable export from West Africa, for use in candle-making, &c. There is usually only one ripe seed in each fruit, those in the abortive ovaries remaining undeveloped; but, occasionally, two or more may ripen. The seeds are large, but the embryo is usually small, and is sunk in a pit in the large perisperm, or albumen. This latter is white, or may be streaked with brown. In some it is fleshy (Cocoa-nut), in others horny (Date); and in the "Ivory Palms" (Phytelephas) it is so compact and hard as to be very largely used as a substitute for real ivory, in the manufacture of billiard balls and many other articles. A noteworthy peculiarity of many Palms is that they have the stems, leaves, and even the spathes and fruits, covered with sharp prickles, usually of a dark colour, which form a most efficient defence against enemies. In some kinds (e.g., Astrocaryum Jauari, &c.), the prickles on the trunk may reach a length of nearly 1ft., and a breadth, at the base, of nearly 1/2in. In certain climbing Palms (species of Calamus and Desmoncus, for instance), the prickles are hooked, or so placed as to assist the plants in climbing; but aid in this is still more efficiently given in Desmoncus and a few Chamaedoreae by certain leaflets, near the end of the leaf, being altered to form strong, recurved hooks. Palmeae are not very closely related to any other order: Juncaceae seem, on the whole, most nearly allied to them. There are from 1100 to 1200 recorded species, though a considerable number of these are not well known. They are almost confined to the tropics, extending beyond these limits in exceedingly reduced numbers. Chamaerops humilis is the only species native in Europe, where it reaches 44deg. N. Lat. The limits of latitude elsewhere are about 34deg. N. in Asia, 36deg. N. in America, 34deg. S. in Africa, 37deg. S. in S. America, in Chili, and 44deg. S. in New Zealand. The leading genera of Palms are noticed in this work, in so far as they are of interest to gardeners; they are too numerous to be repeated here; but several of the more important genera are referred to in this article. Among the richest in species are: Astrocaryum, Attalea, Bactris, Calamus, Caryota, Chamaedorea, Cocos, Desmoncus, Geonoma, Hyphaena, Korthalsia, Licuala, Livistona, Phoenix. In addition to these, there are many genera that, despite the small number of species included in them, are of importance, either as greenhouse plants, or because of their useful products. The genera are almost confined to either the Old World or the New: Raphia, among Calameae, and Elaeis and Cocos, among Cocoinae, alone breaking this rule, out of 132 genera recognised in Bentham and Hooker's "Genera Plantarum," In each case, only one species is common to the two hemispheres. These species are Cocos nucifera (Cocoa-nut), Elaeis guineensis (Oil Palm), and Raphia vinifera. The uses of Palm-trees, and of their products, to natives of tropical lands, are far beyond what it is possible for residents in temperate regions to conceive. The stems of some supply the timber used in building houses, or the laths for forming partitions; while the tough stems, or rind of the stems, of others supply strong cordage for binding together the beams, for chair-making, and for many other household purposes. The stems of others split, and each half hollowed, make aqueducts; and of others the South American Indians make their blow-pipes for shooting out poisoned arrows. The leaves are largely used for thatch, or for walls of houses; for making fans, umbrellas, household utensils, and even tents. From the young leaves of various species fibres are largely prepared, which are used for making hammocks and other durable articles. The leaf-blades of a few are used as paper in the East; and the fibres of several species are employed in paper-making. The coarse, woody bundles that surround the stems of two American Palms are used largely for making besoms, under the name "Piassaba fibre." Two American Palms produce vegetable wax in such abundance as to be worth collecting for sale and export. In Ceroxylon andicola, the wax is formed on all parts of stem and leaves; in Copernicia cerifera, it is found only on the leaves. An Eastern Palm (Calamus draco) yields a resincus, red substance, known as "Dragon's Blood," of an astringent nature, exuded from stems and fruits. Reference has already been made to the preparation of coir from the cocoa-nut, and to the uses of Coquilla nut kernels, and of the perisperm of the Ivory-Palm, for carved ornaments, &c. As yielding food to human beings, Palms are not less valuable. The softer tissues of the interior of the stems of many trees contain large quantities of starchy stuffs, which, when prepared, form the well-known Sago. The greater part of that brought to Europe is obtained from Metroxylon laeve and M. Rumphii. The seedling plants of the Palmyra Palm (Borassus flabelliformis), and the tender tissues of the terminal bud of many Palms, are cooked and eaten in various regions of the tropics. A sweet juice, containing a large amount of sugar, is obtained from cuts in the young tissues of many