THE PALM-STEM.

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centre, and from this again outwards to the periphery,it is clear that in every transverse section of the stem wemust meet with the fibrous inferior extremities of thevascular bundles at the periphery; further in, the thickand hard part of the bundles formed further up; andtoward the middle of the stem, the soft part of thebundles in the situation of their more vertical coursebeneath their point of curvature; finally, we may meetwith the portion of the bundles, in which they run fromthe centre toward the leaves, in the most varied situations,among the others. The last vascular bundles will be cutthrough more or less obliquely, the rest in pretty nearlya fair transverse section.

The examination of such a transverse section by themicroscope, shows that the outer fibrous bundles arecomposed solely of thick-walled prosenchymatous cells,which correspond to the liber-cells of the other vascularbundles. More toward the interior, we meet with largebundles, which already exhibit the perfect composition ofthe vascular bundle; they are distinguished by their liber-mass being relatively very large, and by having the woodconsisting of a single vessel surrounded by but few cells.The proper vessels likewise exist only in small numbers.Further inward, where the vascular bundles have attainedtheir most considerable size, they are composed in greatestpart of thick-walled, lighter or darker brown cells, thewood is still but slightly developed, yet contains alreadyone or two vessels of tolerable size, which are inclosedby few, somewhat thick-walled, cells ; the proper vesselsare also but little developed, and are readily distinguishedfrom the wood-cells by their thinner walls. Still furtherinward, in the transition to the soft part of the stem, the sizeof the vascular bundles diminishes; they exhibit a rounderform, since the liber-mass is considerably smaller andassumes the form of a crescent, in the concavity of whichthe proper vessels are received, and behind these lies thestrongly developed woody portion. In this occur one ortwo large vessels, with several smaller behind them. The

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