THE PALM-STEM. 7 



Isolated species occur with stems sometimes very much abbreviated, and at 

 other times of tolerable length, e. g. Attalea compta. The second variety 

 occurs in Sabal here the stem forms a short, creeping rhizome, of a most 

 remarkable form, its leafy apex lying on the ground, while the hinder ex- 

 tremity is lifted up by the roots, and projects above the ground. 



Note. I had no specimens of this fifth form to examine ; the following 

 remarks relate, therefore, only to the first four forms of stems mentioned. 



Course of the Vascular Bundles in the Stem. 



Before I proceed to the microscopic anatomical de- 

 scription of the stem, it will be necessary to describe the 

 course of the vascular bundles. It is known that these do 

 not lie in concentric circles, but are scattered without 

 definite arrangement throughout the stem. This differ- 

 ence of the Palms from Dicotyledonous trees is so striking, 

 that even in ancient times it was regarded as a charac- 

 teristic peculiarity of Palms.* The course of the vascular 

 bundle is best traced in stems where the parenchyma has 

 lost its firmness by decomposition ; in these the individual 

 bundles may with very little trouble be extricated from a 

 stem split longitudinally. Stems with a white pith-like 

 centre are also very well adapted to this investigation. 

 When, in such a stem, e. g. Kunthia montana, a vascular 

 bundle is traced from the point of insertion of the leaf 

 backward, it is found that it runs in a curve (the con- 

 vexity upward,) to the centre of the stem, then in the 

 neighbourhood of the centre runs down a certain extent 

 deep in the stem, but soon again loses the direction 

 parallel to the axis of the stem, gradually (since at the 

 same time it is always running down the stem) again 

 approaching the surface, till it lies beneath the rind, and 

 there passes down the stem beneath this. 



Otis. I have here described the course of the* vascular bundle in the 

 direction from above downward, because I usually traced them in this 



* Theophrast., Hist. Plant., lib. i, cap. ix. 



