THE PALM-ROOT. 47 



successively finer portions, apply themselves upon the vas- 

 cular bundles of the stem, and there terminate. 



Besides this connexion with the interior of the stem, 

 the root is most intimately connected with fibrous layer 

 by means of its cortical portion; for, into the cortical 

 portion of each root penetrates a portion of the evascular 

 fibrous bundles of the stem. In some roots, as in those 

 of Cocos and Plicenix, the little fibrous bundles run still 

 further out into the roots, and then lose themselves gra- 

 dually ; in others, as in Diplothemium maritimum, Sabal 

 Adansonii, they are at once lost at the very beginning of 

 the root. 



In Dracaena Draco., also, I observed that the outer, fibrous, firm layer of the 

 stem penetrated the roots, was continued some distance in this, and formed 

 a sheath round its central body, which was far stronger and longer on the 

 side turned towards the surface of the earth than on the under. This 

 fibrous layer was gradually attenuated, and altogether lost in the distance 

 of a few inches. It is clear from this, that the opinion of Dupetit-Thouars, 

 that the roots are formed of the fibres running down from the leaves and 

 buds, is totally erroneous. 



The roots of different Palms possess a very similar 

 organization. That of Diplothemium maritimum may 

 serve as an example. In the cross section, it is seen that 

 in the central bundle all the vessels lie toward the cir- 

 cumference, and the middle is formed solely of cells. 

 The vessels are constantly placed in such a manner that 

 the largest are nearest the centre, the smallest nearest the 

 circumference ; therefore the condition is the contrary of 

 that which we have met with in the stem. The vessels 

 do not lie, as in the vascular bundles of the stem, irre- 

 gularly scattered and isolated, but in rows, which are 

 directed from the centre toward the circumference, and 

 these rows are frequently split toward the exterior into 

 two diverging arms. The largest of these vessels present 

 the form of reticulated vessels, and are composed of rather 

 short tubes, possessing reticularly perforated septa at their 

 ends. The small vessels, situated more externally, ex- 

 hibit the form of porous and scalariform ducts. In 



