The Natural History of Pliny, Volume 3 · the Elder Pliny
CHAP. 36.—LEAVES WHICH TURN ROUND EVERY YEAR.
We find a most remarkable and, indeed, a marvellous peculiarity[2441] existing in the elm, the lime, the olive, the white poplar, and the willow; for immediately after the summer solstice the leaves of these trees turn completely round; indeed, we have no sign which indicates with greater certainty that that period has past. (24.) These trees also present in their leaves the same difference that is to be observed in those of all the rest: the underside, which looks towards the ground, is of a green, grassy colour, and has a smooth surface;[2442] while the veins, the callous skin, and the articulations, lie upon the upper face, the veins making incisions in the parts beneath, like those to be seen upon the human hand. The leaf of the olive is whiter above, and not so smooth; the same is the case, too, with that of the ivy. The leaves of all trees turn[2443] every day towards the sun, the object being that the under side may be warmed by its heat. The upper surface of them all has a down upon it, in however small quantity it may be; in some countries this down is used as a kind of wool.[2444] CHAP. 37.—THE CARE BESTOWED ON THE LEAVES OF THE PALM, AND THE USES TO WHICH THEY ARE APPLIED. We have already said[2445] that in the East strong ropes are made of the leaves of the palm, and that they are improved by lying in the water. Among ourselves, too, the leaves of the palm are generally plucked immediately after harvest, the best being those that have no divisions in them. These leaves are left to dry under cover for four days, after which they are spread out in the sun, and left out in the open air all night, till they have become quite white and dry: after this they are split before they are put to any use.
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