46 THE GEOGRAPHY OF PLANTS. 



All these, however, are far distanced by the 

 tree which has led to these remarks the Baobab 

 of Senegal, one of which was estimated to be 

 5,150 years old ; yet baron Humboldt con- 

 siders a cypress in the garden Chapullepec to 

 be still older; it had already reached a great ag^ 

 when Montezuma was on the throne of Mexico, 

 in 1520. But to return from this digression : 

 the Bombax, or silk cotton tree, is another of 

 these equinoctial trees of gigantic life. From 

 the excessive abundance of the pith, its trunks 

 increase prodigiously in thickness, and lose 

 the common cylindrical shape, appearing like 

 huge casks, thirty or forty feet high, and of 

 proportionate circumference. It is often em- 

 ployed for making canoes, and a single trunk 

 has been known to hold one hundred and fifty 

 men. It derives its name from the silky cha- 

 racter of the hairs, which surround the seeds 

 just as the wool of the true cotton does. It 

 cannot, however, be spun into threads, the 

 peculiar smoothness of the hairs preventing 

 them from binding together, while on the true 

 cotton there are minute roughnesses on the 

 filaments, which materially serve this purpose. 



Among the other gigantic trees of the equi- 

 noctial zone, we may mention various species of 

 the Mimosa, (often called Acacia,) the maho- 

 gany tree, (Sivietenia^) the Brazil wood, (Ccesal- 

 pinia,) the locust tree, (Hymenwa,) bread fruit 

 tree, (Artocarpus,) cashew nut, (Anacardium,) 

 custard apple, (Anona,) etc. Martins repre- 

 sents a scene in Brazil, where some trees of the 



