270 POPULAR GEOGRAPHY OF PLANTS. 



ferent race altogether, with many of which we have already 

 made acquaintance in the Tropical Zone, namely, those 

 gigantic dicotyledonous trees with large leaves (unlike the 

 tender green foliage they wear in colder climates) and 

 trunks of enormous thickness, amongst which some of the 

 first in importance are the great unshapely Silk Cotton 

 trees (JBombacea) . " Prom their excessive development of 

 pith they increase prodigiously in thickness, till they lose 

 the common cylindrical shape, and resemble instead huge 

 casks, thirty or forty feet in height, and of proportionate 

 circumference/' 



Bivalling the Silk Cotton trees in their swelled gigantic 

 trunks, stand the peculiar- looking tropical Pig-trees. Before 

 mentioning any others, we must remember that, grandees as 

 they are, these two giants have some very near relations 

 whose names are " household words" with us ; the Silk 

 Cotton trees, from the valvate calyx and columnar stamens 

 of their blossoms, are closely allied to the Mallow tribe; 

 and the Eig-trees, for equally good reasons, as has been 

 mentioned before, must own that they are near akin to the 

 race of Nettles. But the greatest of the vegetable world, 

 in point of size, are the monster Baobab-trees (Adansonia 

 digitata), which, though they belong to a tribe called Ster- 



