Palm Tree

Worldwide, the family Palmae (Palm Tree) is composed of over 230 genera and about 3000 species. Only a few of these are indigenous to the continental United States, and most of these are restricted to the warmer regions of southern United States, southern Florida and southern California. However, a large number of exotic species have been imported for ornamental purposes and a few of these have become widely naturalized.

Palm Tree, for identification purposes. can be divided into two major groups: those that have palmate or fan-shaped leaves; and those that have pinnate, or feather-shaped leaves. The palmate-leaved species are characterized by a leaf structure in which all leaf segments arise from a single point, similar to the structure of a human hand. Pinnate leaves are characterized by leaves along each side of a central axis, similar in design to that of a feather.

Palm Tree (Palmaceae) have been termed the princes of the vegetable kingdom. Neither the anatomy of the Palm Tree stems nor the conformation of Palm Tree flowers, however, entitles them to any such high position in the vegetable hierarchy. Palm Tree stems are not palmjpg

more complicated in structure than those of the common butcher’s broom (Ruscus); their flowers are for the most part as simple as those of a rush (Juncus). The order Palmaceae is characterized among monocotyledonous plants by the presence of an unbranched stem bearing a tuft of leaves at the extremity only, or with the leaves scattered; these leaves, often gigantic in size, being usually firm in texture and branching in a pinnate or palmate fashion. The flowers are borne on simple or branching spikes, very generally protected by a spathe or spathes, and each consists typically of a perianth of six greenish, somewhat inconspicuous segments in two rows, with six stamens, or pistil of 1-3 carpel's, each with a single ovule and a succulent or dry fruit. The seed consists almost exclusively of endosperm, Upper portion of Coconut seed, albumen in a cavity in showing the embryo, embedded in endosperm, which is lodged the relatively very minute embryo. These are the general characteristics by which this very well-defined order may be discriminated, but, in a group containing considerably more than a thousand species, deviations from the general plan of structure occur with some frequency. As the characteristic appearances of palms depend to a large extent upon these modifications, some of the more important among them may briefly be noticed.

Palm Tree - Stems

Taking the stem first, we may mention that it is in very many palms relatively tall, erect, unbranched, regularly cylindrical, or dilated below so as to form an elongated cone, either smooth, or covered with the projecting remnants of the former leaves, or marked with circular scars indicating the position of those leaves which have now fallen away. It varies in. diameter from the thickness of a reed (as in Chamaedorea) to a sturdy pillar-like structure as seen in the date-palm, Palmyra palm or Talipot. In other cases the very slender stem is prostrate, scandent by means of formidable hooked prickles which, by enabling the plant to support itself on. the branches of neighboring trees, also permit the stem to grow to a very great length and so to expose the foliage to the light and air above the tree-tops of the dense forests these palms grow in,’ as in the genus Calamus, the Rattan or Cane palms. In. some few instances the trunk, or that portion of it which is above ground, is so short that the plant is in a loose way called “ stemless “ or “ acaulescent,” as in Geonoma, and as happens sometimes in the only species found in a wild state in Europe, Chamaerops humus. The vegetable ivory (Phytelephas) of equatorial America has a very short thick stem bearing a tall cluster of leaves which appears to rise from the ground. In many species the trunk is covered with a dense network of stiff fibers, often compacted together at the free ends into spines. This fibrous material, which is so valuable for cordage, consists of the fibrous tissue of the leafstalk, which in these cases persists after the decay of the softer portions. It is very characteristic of some palms to produce from the base of the stem a series of adventitious roots which gradually thrust themselves into the soil and serve to steady the tree and prevent its overthrow by the wind. The underground stem of some species, e.g. of Calamus, is a rhizome, or root-stock, lengthening in a more or less horizontal manner by the development of the terminal bud, and sending up lateral branches like suckers from the root-stock, which form dense thickets of cane-like stems. The branching of the stem above ground is unusual, except in the case of the Doum palm of Egypt (Hyphaene) , where the stem forks, often repeatedly; this is due to the development of a branch to an equal strength with the main stem. In other cases branching, when present, is probably the result of some injury to the terminal bud at the top of the stem, in consequence of which buds sprout out from below the apex.

The internal structure of the stem does not differ fundamentally from that-of a typical monocotyledonous stem, the taller, harder trunks owing their hardness not only to the fibrous or woody skeleton but also to the fact that, as growth goes on, the originally soft cellular ground tissue through which the fibers run becomes hardened by the deposit of woody matter within the cells, so that ultimately the cellular portions become as hard as the woody fibrous tissue.

Palm Tree Types - Leaves Information

The leaves of the palm are either arranged at more or less distant intervals along the stem, as in the canes, or are approximated in tufts at the end of the stem, thus forming those noble crowns of foliage which are so closely associated with the general idea of a palm. In the young condition, while still unfolded, these Palm leaves, with the succulent end of the stem from which they arise, form “the cabbage,” which in some Palm species is highly esteemed as an article of food.

The adult Palm tree leaf generally presents a sheathing base tapering upwards into the stalk or petiole, and this again bearing the lamina or blade. The sheath and the petiole very often bear stout spines, as in the rattan palms and when, in course of time, the upper parts of the leaf decay and fall off, the base of the Palm leaf-stalk and sheath often remain, Texas Sabal Palm

either entirely or in their fibrous portions only, which latter constitute the investment to the Palm tree stem already mentioned. In size the leaves vary within very wide limits, some being only a few inches in extent, while those of the noble Carycta I , may be measured in tens of feet. In form the leaves of palms are very rarely simple; usually they are more or less divided, sometimes, as in Caryota, extremely so. In Palm tree species of Geonoma, Vers chaffeltia and some others, the leaf splits into two divisions at the apex and not elsewhere; but more usually the leaves branch regularly. The form of the segments is generally more or less linear, but a very distinct appearance is given by the broad wedge-shaped leaflets of such palms as Caryotct, Martinezia or Mauritia. These forms run one into another by transitional gradations; and even in the same palm the form of the leaf is often very different at different stages of its growth, so that it is a difficult matter to name correctly seedling or juvenile palms in the condition in which we generally meet with them in the nurseries, or even to foresee what the future development of the plant is likely to be. Like the other parts of the plant, the leaves are sometimes invested with hairs or spines; and, in some instances, as in the magnificent Ceroxylon andicola, the under surface is of a glaucous white or bluish color, from a coating of wax.

The inflorescence of palm trees consists generally of a fleshy spike, either simple or much branched, studded with numerous, sometimes extremely numerous, flowers, and enveloped by one or more sheathing bracts called “ spathes “. These parts may be small, or they may attain relatively enormous dimensions, hanging down from amid the Palm crown of foliage like huge tresses, and adding greatly to the noble effect of the tree's leaves. In some cases, as in the Talipot palm, the tree only flowers once; it grows for many years until it has become a large tree then develops a huge inflorescence, and after the fruit has ripened, the Palm tree dies.

Palm Tree - Flowers

The individual Palm flowers are usually small (figs. 3, 6), greenish and insignificant; their general structure has been mentioned already. Modifications from the Palm typical structure arise from difference of texture, and specially from suppression of parts, in consequence of which the Palm flowers are very generally unisexual, though the flowers of the two sexes are generally produced on the same tree (monoecious), not indeed always in the same season, for a Palm tree in one year may produce all male flowers and in the next all female flowers. Sometimes the Palm tree flowers are modified by an increase in the number of parts; thus the usually six stamens may be represented by I2’to 24 or even by hundreds. The carpel's are usually three in number, and more or less combined; but they may be free, and their number may be reduced to two or even one. In any case each carpel contains but a single ovule.

Owing to the sexual arrangements before mentioned for the Palm, the pollen has to be transported by the agency of the wind or of insects to the Palm Tree's female flowers. This is facilitated sometimes by the elastic movements of the stamens and anthers, which liberate the pollen so freely at certain times that travelers speak of the datepalms of Egypt (Phoenix dactylifera) being ‘at daybreak hidden in a mist of pollen grains. In other Palm tree cases fertilization is effected by the agency of man, who removes the male flowers and scatters the pollen over the fruit-bearing trees. This practice has been followed in the case of the date from time immemorial; and it afforded one of the earliest and most irrefragable proofs by means of which the sexuality of plants was finally established. In the course of ripening of the fruit two of the carpel's with their ovules may become absorbed, as in the coco-nut, the fruit of which contains only one seed though the three carpel's are indicated by the three longitudinal sutures and by the presence of three germ-pores on the hard endocarp.

Palm Tree - Fruit

The Palm tree fruit is various in form, size and character; sometimes, as in the common date from a Palm is a berry with a fleshy rind enclosing a hard stony kernel, the true seed; the fruit of Areca is similar; sometimes it is a kind of drupe as in Acrccomia, or the coconut, Cocos nucif era, where the fibrous central portion investing the hard shell corresponds to the fleshy portion of a plum or cherry, while the shell or nut corresponds to the stone of stone-fruits, the seed being the kernel. In Borassus the three seeds are each enclosed in a separate chamber formed by the stony endocarp. Sometimes, as in the species of Metroxylon, Raphia, Daemonorops, &c,, the Palm tree fruit is covered with hard, pointed, reflexed shining scales, which give the Palm a very remarkable appearance.

Palm Tree - Seeds

The Palm tree seeds show a corresponding variety in size and shape, but always consist of a mass of Palm endosperm, in which is embedded a relatively very minute embryo. The hard stone of the date palm is the endosperm, the white oily flesh of the coco-nut is the same substance in a softer condition; the so-called “vegetable ivory” is derived from the endosperm of Phytelephas. In some Palm tree genera the inner seed coat becomes thickened along the course of the vascular bundles and growing into the endosperm produces the characteristic appearance in section known as ruminate—this is well shown in the Areca nut.

Palm Tree - Family

The order (Palm Tree) contains 32 genera with about 1100 species mainly tropical, but with some Palms in warm temperate regions. Chamaerops humilis is a native of the Mediterranean region, and the date-palm yields fruit in southern Europe. as far north as 38° N. latitude. In eastern Asia the Palm, like other tropical families, extend along the coast reaching Korea and the south of Japan. In America a few’ small genera occur in the southern United States and California; and in South America the southern limit is reached in the Chilean genus Juhaea (the Chile coco-nut) at 37° S. latitude. The great centers of distribution are tropical America and tropical Asia; tropical Africa contains only 2 genera, though some of the species, like the Doum Palm Tree (Hyphaene thebaica) and the Deleb or Palmyra palm tree(Borassusfiabellifer) have a wide distribution. With three exceptions Old and New World forms are distinct—the coco-nut (Cocos nucifera) is widely distributed on the coasts of tropical Africa, in India and the South Seas, the other species of the genus Palm are confined to the western hemisphere. The oil palm tree (Elaeis guineensis) is a native of west tropical Africa, the other Palm species of the genus is tropical American. Raphia has also species in both tropical Africa and tropical America.