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 layerby means of its cortical portion; for, into the corticalportion of each root penetrates a portion of the evascularfibrous bundles of the stem. In some roots, as in thoseof Cocos and Phoenix, the little fibrous bundles run stillfurther out into the roots, and then lose themselves gra-dually ; in others, as in Diplothemium maritimum, SabalAdansonii, they are at once lost at the very beginning ofthe root.

In Dracana Draco, also, I observed that the outer, fibrous, firm layer of thestem penetrated the roots, was continued some distance in this, and formeda sheath round its central body, which was far stronger and longer on theside turned towards the surface of the earth than on the under. Thisfibrous layer was gradually attenuated, and altogether lost in the distanceof a few inches. It is clear from this, that the opinion of Dnpetit-Thouars,that the roots are formed of the fibres running down from the leaves andbuds, is totally erroneous.

The roots of different Palms possess a very similarorganization. That of JDiplotAemivm maritimum mayserve as an example. In the cross section, it is seen thatin 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 thatthe largest are nearest the centre, the smallest nearest thecircumference; therefore the condition is the contrary ofthat which we have met with in the stem. The vesselsdo not lie, as in the vascular bundles of the stem, irre-gularly scattered and isolated, but in rows, which aredirected from the centre toward the circumference, andthese rows are frequently split toward the exterior intotwo diverging arms. The largest of these vessels presentthe form of reticulated vessels, and are composed of rathershort tubes, possessing reticularly perforated septa at theirends. The small vessels, situated more externally, ex-hibit the form of porous and scalariform ducts. In