There is also another tree similar to the preceding one, but with a thicker foliage, and a blossom like the rose. This flower shuts[491] at night, and, beginning to open towards sun-rise, appears in full blow by mid-day; the natives are in the habit of saying that in this way it goes to sleep. The same island bears also the palm, the olive, the vine, and the fig, with various other kinds of fruit. None of the trees in this island lose their leaves;[492] it is abundantly watered by cool streams, and receives the benefit of rain. CHAP. 24.—THE VARIOUS USEFUL PRODUCTS OF TREES. Arabia, which is in the vicinity of these islands, requires that we should make some distinction in its vegetable products, seeing that here the various parts of trees which are employed for useful purposes are the root, the branches, the bark, the juices, the gum, the wood, the shoots, the blossoms, the leaves, and the fruit. CHAP. 25. (12.)—COSTUS. A root and a leaf, however, are the productions which are held in the very highest estimation in India. The root is that of the costus;[493] it has a burning taste in the mouth, and a most exquisite odour; in other respects, the branches are good for nothing. In the island of Patale,[494] situate at the very mouth of the river Indus, there are two kinds of costus found, the black and the white; the last is considered the best. The price of it is five denarii per pound. CHAP. 26.—NARD. THE TWELVE VARIETIES OF THE PLANT. Of the leaf, which is that of the nard,[495] it is only right to speak somewhat more at length, as it holds the principal place among our unguents. The nard is a shrub with a heavy, thick root, but short, black, brittle, and yet unctuous as well; it has a musty smell, too, very much like that of the cyperus, with a sharp, acrid taste, the leaves being small, and growing in tufts. The heads of the nard spread out into ears; hence it is that nard is so famous for its two-fold production, the spike or ear, and the leaf. There is another kind, again, that grows on the banks of the Ganges, but is altogether condemned, as being good for nothing; it bears the name of ozænitis,[496] and emits a fetid odour. Nard is adulterated with a sort of plant called pseudo-nard,[497] which is found growing everywhere, and is known by its thick, broad leaf, and its sickly colour, which inclines to white. It is sophisticated, also, by being mixed with the root of the genuine nard, which adds very considerably to its weight. Gum is also used for the same purpose, antimony, and cyperus; or, at least, the outer coat of the cyperus. Its genuineness is tested by its lightness, the redness of its colour, its sweet smell, and the taste more particularly, which parches the mouth, and leaves a pleasant flavour behind it; the price of spikenard is one hundred denarii per pound.