trees correspond the 'eye' in the vine, the joint in the reed). . . . . In some trees again there occurs, as it were, a diseased formation of small shoots, as in elm oak and especially in the plane; and this is universal if they grow in rough waterless or windy spots. Apart from any such cause this affection occurs near the ground in what one may call the 'head' of the trunk, when the tree is getting old.
Some trees again have what are called by some 'excrescences' (or something corresponding), as the - olive; for this name belongs most properly to that tree, and it seems most liable to the affection; and some call it 'stump, some krotone, others have a different name for it. It does not occur, or only occurs to a less extent, in straight young trees, which have a single root and no side-growths. To the olive also, both wild and cultivated, are peculiar certain thickenings in the stem.
As to habit.
IX. Now those trees which grow chiefly or only in the direction of their height are such as silver-fir date-palm cypress, and in general those which have a single stem and not many roots or branches (the date-palm, it may be added, has no side-growths at all), And trees like these have also similar growth downwards. Some however divide from the first,
