“The palms, as a natural group, stand out among all other plants with remarkable distinctness and individuality. And yet this common character, uniting them so closely as a natural order, does not prevent the most striking difference between various kinds of palms. As a whole, no family of trees is more similar; generically and specifically none is more varied, even though other families include a greater number of species. Their differences seem to me to be determined in a great measure by the peculiar arrangement of their leaves; indeed, palms, with their colossal leaves, few in number, may be considered as ornamental diagrams of the primary laws according to which the leaves of all plants throughout the whole vegetable kingdom are arranged; laws now recognized by the most advanced botanists of the day, and designated by them as Phyllotaxis. The simplest arrangement in these mathematics of the vegetable world is that of the grasses, in which the leaves are placed alternately on opposite sides of the stem, thus dividing the space around it in equal halves. As the stem of the grasses elongates, these pairs of leaves are found scattered along its length; and it is only in ears or spikes of some genera that we find them growing so compactly on the axis as to form a close head. Of this law of growth the palm known as the Baccába of Pará (Œnocarpus distychius) is an admirable illustration; its leaves being disposed in pairs one above another at the summit of the stem, but in such immediate contact as to form a thick crown. On account of this disposition of the leaves, its appearance is totally different from that of any other palm with which I am acquainted. I do not know any palm in which the leaves are arranged in three directions only, as in the reeds and sedges of our marshes, unless it be the Jacitara (Desmonchus), whose winding slender stem, however, makes the observation uncertain. An arrangement in five different directions is common in all those palms which, when young, have only a cluster of five fully developed leaves above the ground, with a spade-like sixth leaf rising from the centre. When full grown, they usually exhibit a crown of ten or fifteen leaves and more, divided into tiers of five, one above the other, but so close together that the whole appears like a rounded head. Sometimes, however, the crown is more open, as in the Maximiliana regia (Inaja), for instance, in which the stem is not very high, and the leaves, always in cycles of five, spread slightly, so as to form an open vase rising from a slender stem. The Assai (Euterpe edulis) has an eight-leaved arrangement, and has never more than a single cycle of leaves, though it may sometimes have seven leaves when the first of the old cycle has dropped, before the ninth, with which the new cycle begins, has opened; or nine, if the first leaf of the new cycle (the ninth in number) has opened, before the first of the old cycle has dropped.