Page:Popular Science Monthly Volume 60.djvu/401

This page has been proofread, but needs to be validated.

the fronds to their very tips. When the size of the leaves of some of the Amazonian palms is recalled—as large as a man can carry—it will be recognized that these bundles must be very strong. PSM V60 D401 Palm trunk cross section showing the fibro vascular bundles and frond bases.pngFig. 8. Cross Section of a Palm Trunk showing the usual Arrangement of the Fibro-vascular Bundles. The fibro-vascular bundles pass out from the palm trunk into the fronds. In Gray's text-book of botany a short longitudinal section of a palm trunk is shown, in which these bundles are represented as coming to the surface very much at random. As a matter of fact they reach the surface only at the leaf scars.[1]

The most important use to which palm trunks are fig. 8. Cross section put is probably the manufacture of rattan or 'cane' used to bottom chairs. The rattan palm (Calamus) does not grow in Brazil, but the Jacitara and Urumbámba (Desmoncus) are palms of similar habits, PSM V60 D401 Palm trunk cross section showing the fibro vascular bundles.pngFig. 9. Section of a Palm Trunk showing the Relation of the Fibro-vascular Bundles to the Frond Basks.though they do not seem to lend themselves to this sort of use as readily as the Calamus.

Foliage.—The foliage of the trunked palm, unlike that of most plants, is all at the summit of the single stem.[2]

The fronds of most of them form a compact symmetrical cluster, but there is one kind of bacába (Oenocarpus distichus) that has its fronds arranged in a single plane like a gigantic open fan.

The gracefulness of palms is mostly due to the symmetry of the plants combined with the flexibility of the fronds and leaflets. In the length and size of their leaves many of the palms surpass all other forms of vegetation. In detail the foliage varies quite as much as do the trunks. The palmate leaf from which the 'palm leaf fans' are made is familiar to every one. Some of the palmate leaves, however, reach an almost incredible size. The great murity of the Amazonas region often has its palmate leaves so large that a man, unaided, cannot lift a single leaf. The palmate leaves are entire, as a rule, but there is at least one species that has the leaf deeply bifid or split down the middle into two equal parts.

  1. The course and growth of the fibro-vascular bundles in palms. 'Proe. Am. Phil. Sec.,' 1884, XXI., 459-483.
  2. The branching doom palm of Africa (Hyphaene thebaica) is the only exception to this rule. There is an Areca that forks near the base, and the date palm puts out shoots at or near the base of the trunk.