The robur, in addition to its fruit, has a great number of other productions: it bears[2257] the two varieties of the gall-nut, and a production which closely resembles the mulberry,[2258] except that it differs from it in being dry and hard: for the most part it bears a resemblance to a bull’s head, and in the inside there is a fruit very similar to the stone of the olive. Little balls[2259] also are found growing on the robur, not unlike nuts in appearance, and containing within them a kind of soft wool, which is used for burning in lamps; for it will keep burning without oil, which is the case also with the black gall-nut. It bears another kind, too, of little ball, covered with hair,[2260] but used for no purpose: in spring, however, this contains a juice like honey. In the hollows formed by the union of the trunk and branches of this tree there are found also small round balls,[2261] which adhere bodily to the bark, and not by means of a stalk: at the point of junction they are white, but the rest of the body is spotted all over with black: inside they are of a scarlet colour, but on opening them they are found to be empty, and are of a bitter taste. Sometimes, too, the robur bears a kind of pumice,[2262] as well as little balls, which are formed of the leaves rolled up; upon the veins of the leaves, too, there are watery pustules, of a whitish hue, and transparent while they are soft; in these a kind of gnat[2263] is produced, and they come to maturity just in the same way that the ordinary gall-nut does. CHAP. 11. (8.)—CACHRYS. The robur bears cachrys,[2264] too; such being the name given to a small round ball that is employed in medicine for its caustic properties. It grows on the fir likewise, the larch, the pitch-tree, the linden, the nut-tree, and the plane, and remains on the tree throughout the winter, after the leaves have fallen. It contains a kernel very similar to that of the pine-nut, and increases in size during the winter. In spring the ball opens throughout, and it finally drops when the leaves are beginning to grow. Such is the multiplicity of the products borne by the robur in addition to its acorns; and not only these, but mushrooms[2265] as well, of better or worse quality, the most recent stimulants that have been discovered for the appetite; these last are found growing about its roots. Those of the quercus are the most highly esteemed, while those of the robur, the cypress, and the pine are injurious.[2266] The robur produces mistletoe[2267] also, and, if we may believe Hesiod,[2268] honey as well: indeed, it is a well-known fact, that a honey-like[2269] dew falling from heaven, as we have already mentioned,[2270] deposits itself upon the leaves of this tree in preference to those of any other. It is also well known that the wood of this tree, when burnt, produces a nitrous[2271] ash. CHAP. 12.—THE KERMES BERRY.