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[1] the two varieties of the gall-nut, and a production which closely resembles the mulberry,[2] 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[3] 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,[4] 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,[5] 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,[6] 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[7] is produced, and they come to maturity just in the same way that the ordinary gall-nut does.

1. The ancients were not aware that the gall was produced from the eggs of the cynips, deposited upon the leaf or bark of the tree. Tan and gallic acid are its principal component parts.

2. A substance quite unknown now; but it is very doubtful if Pliny is rightly informed here.

3. A fungous gall, produced by the Cynips fungosa. It is not used for any domestic purpose at the present day.

4. This kind of gall is now unknown. Fée questions the assertion about its juice.

5. The Cynips quercus baccarum of Linnæus, one of the common galls.

6. The root cynips, the Cynips radicum of Fourcroi, produces these galls, which lie near the root, and have the appearance of ligneous nodo- sities. It is harder than wood, and contains cells, in which the larva of the insect lies coiled up.

7. This is a proof, as Fée remarks, that the ancients had observed the existence of the cynips; though, at the same time, it is equally evident that they did not know the important part it acts in the formation of the gall.