CHAP. 10.—OTHER PRODUCTIONS ON THESE TREES BESIDES THE ACORN.
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.