These mowana-trees are the most wonderful examples of vitality in the country; it was therefore with surprise that we came upon a dead one at Tlomtla, a few miles beyond this spot. It is the same as those which Adamson and others believed, from specimens seen in Western Africa, to have been alive before the flood. Arguing with a peculiar mental idiosyncracy resembling color-blindness, common among the French of the time, these savans came to the conclusion that "therefore there never was any flood at all." I would back a true mowana against a dozen floods, provided you do not boil it in hot sea-water; but I can not believe that any of those now alive had a chance of being subjected to the experiment of even the Noachian deluge. The natives make a strong cord from the fibres contained in the pounded bark. The whole of the trunk, as high as they can reach, is consequently often quite denuded of its covering, which in the case of almost any other tree would cause its death, but this has no effect on the mowana except to make it throw out a new bark, which is done in the way of granulation. This stripping of the bark is repeated frequently, so that it is common to see the lower five or six feet an inch or two less in diameter than the parts above; even portions of the bark which have broken in the process of being taken off, but remain separated from the parts below, though still connected with the tree above, continue to grow, and resemble closely marks made in the necks of the cattle of the island of Mull and of Caffre oxen, where a piece of skin is detached and allowed to hang down. No external injury, not even a fire, can destroy this tree from without; nor can any injury be done from within, as it is quite common to find it hollow; and I have seen one in which twenty or thirty men could lie down and sleep as in a hut. Nor does cutting down exterminate it, for I saw instances in Angola in which it continued to grow in length after it was lying on the ground. Those trees called exogenous grow by means of successive layers on the outside. The inside may be dead, or even removed altogether, without affecting the life of the tree. This is the case with most of the trees of our climate. The other class is called endogenous, and increases by layers applied to the inside; and when the hollow there is full, the growth is stopped--the tree must die. Any injury is felt most severely by the first class on the bark; by the second on the inside; while the inside of the exogenous may be removed, and the outside of the endogenous may be cut, without stopping the growth in the least. The mowana possesses the powers of both. The reason is that each of the laminae possesses its own independent vitality; in fact, the baobab is rather a gigantic bulb run up to seed than a tree. Each of eighty-four concentric rings had, in the case mentioned, grown an inch after the tree had been blown over. The roots, which may often be observed extending along the surface of the ground forty or fifty yards from the trunk, also retain their vitality after the tree is laid low; and the Portuguese now know that the best way to treat them is to let them alone, for they occupy much more room when cut down than when growing.
The wood is so spongy and soft that an axe can be struck in so far with a good blow that there is great difficulty in pulling it out again. In the dead mowana mentioned the concentric rings were well seen. The average for a foot at three different places was eighty-one and a half of these rings. Each of the laminae can be seen to be composed of two, three, or four layers of ligneous tubes; but supposing each ring the growth of one year, and the semidiameter of a mowana of one hundred feet in circumference about seventeen feet, if the central point were in the centre of the tree, then its age would lack some centuries of being as old as the Christian era (1400). Though it possesses amazing vitality, it is difficult to believe that this great baby-looking bulb or tree is as old as the Pyramids.
The mopane-tree ('bauhinia') is remarkable for the little shade its leaves afford. They fold together and stand nearly perpendicular during the heat of the day, so that only the shadow of their edges comes to the ground. On these leaves the small larvae of a winged insect appear covered over with a sweet, gummy substance. The people collect this in great quantities, and use it as food;* and the lopane--large caterpillars three inches long, which feed on the leaves, and are seen strung together--share the same fate.
* I am favored with Mr. Westwood's remarks on this insect as follows:
"Taylor Institution, Oxford, July 9, 1857.