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 Something similar to this, but even more surprising, occurs in those plants which emit roots from their leaves, as they say does a certain herb which grows about Opus, which is also sweet to taste. The peculiarity again of lupins is less surprising, namely that, if the seed is dropped where the ground is thickly overgrown, it pushes its root through to the earth and germinates because of its vigour. But we have said enough for study of the differences between roots.

VIII. One may take it that the following are the differences between trees:—Some have knots, more or less, others are more or less without them, whether from their natural character or because of their position. But, when I say 'without knots,' I do not mean that they have no knots at all (there is no tree like that, but, if it is true of any plants, it is only of other kinds, such as rush bulrush galingale and plants of the lake side generally) but that they have few knots. Now this is the natural character of elder bay fig and all smooth-barked trees, and in general of those whose wood is hollow or of a loose texture. Olive fir and wild olive have knots; and some of these grow in thickly shaded windless and wet places, some in sunny positions exposed to storms and winds, where the soil is light and dry; for the number of knots varies between trees of the