546 STEM OP PALMS ; GEOGRAPHICAL DISTRIBUTION. 



of that country prevented it, by giving out that he would destroy 

 all these palms on the first approach of the enemy, and by that 

 means cut off all supplies of food from them during the siege. 

 The facts that had been well ascertained by the experience 

 of ages respecting the Date-Palm, were very important to 

 Linnaeus, in supporting the doctrine of the relative functions of 

 the stamens and pistil, of which he was the first to give a correct 

 exposition ; for although this is now universally admitted to be 

 correct, it was at first, like other novel doctrines, most vigor- 

 ously opposed by many. 



723. The Stems of Palms are the best of all examples of 

 Endogenous structure. They are frequently so dense externally, 

 as to bear the stroke of a sharp hatchet without injury. This is 

 caused by the very close interweaving of the woody bundles that 

 descend from the leaves, with those previously forming the exte- 

 rior ; for although they at first pass down through the soft centre 

 of the stem, they direct themselves outwards near its bottom, 

 and penetrate like roots into the exterior mass of fibres already 

 thickly interwoven. In most of the species with long slender 

 trailing stems, the exterior is additionally hardened by a copious 

 deposition of silex, as in the Grasses ; this is especially the case 

 in the Rattan, which will readily strike fire with steel. 



724. Palms are exclusively confined to the regions bordering 

 on the tropics in both hemispheres. They scarcely range beyond 

 40 north and south of the equator ; but particular species are 

 found somewhat beyond these limits. Their chief habitation is 

 South America, where they mostly abound in the low and humid 

 parts of the country, though some species rise upon the sides of 

 mountains, almost to the limits of perpetual snow. In general 

 each species is confined within very narrow limits ; it is related 

 by Humboldt, that in travelling through the central part o* 

 South America, he found a new species at almost every fifty 

 miles. Although nearly two-thirds of the Palms at present 

 known are natives of South America, none have yet been found 

 in South Africa, where the distance from the Equator is the 

 same. Some species, however, appear to be very easily spread 

 by the agency of Man, or by natural causes ; and this, by the 



