Theophrasti De Historia Plantarum (1483 Incunabulum)

They produce [them]. These are in the category of trees, but the ivy and the bramble are of the category of shrubs. The reed original: "harundo" and the little cedar original: "cedrula" exist, for there is a certain small thing that never becomes a tree. Among the sub-shrubs and herbs are: rue, cabbage, rose, violet, southernwood original: "abrotonum", savory original: "sansucum", wild thyme original: "serpillus", origanum, celery, smallage, poppy, and many kinds of wild plants. Some of these also persist at the top while the rest are lost, such as celery, smallage, and origanum. For even rue is afflicted and changed.

Indeed, all plants—both in these and in other categories that are perpetually green—have narrower leaves, a certain oiliness, and they give off a pleasant scent. Some, although they cannot live forever by their own nature, nevertheless never shed their leaves due to the location, as has been said regarding those that grow in the Elephantine fields and Memphis. But the part that is below the area they call the Delta, from its triangular shape, intercepts time so that they do not remain green forever. On the island of Crete, in the territory of Cortyna, they assert that a plane tree stands near a certain spring that never loses its leaves. They tell the fable that Jupiter slept under it with Europa. There is an oak in the territory of Turin, where the river Sybaris is visible, that never sheds its leaves. They say it does not sprout along with the others, but only after the rising of the Dog Star original: "canicula". They report that there is such a plane tree in Cyprus as well.

For everyone, the leaves fall in autumn and throughout autumn. In some, it happens faster; in others, later, so that some are even overtaken by winter. The loss of leaves does not correspond to germination in such a way that those which sprouted earlier shed their leaves earlier. But some germinate quite prematurely and yet do not shed their leaves any sooner than the others. On the contrary, in some, they begin later, such as the almond tree. Some are accustomed to be late in germinating, but—if I may say so—they do not shed their leaves any later than the others, such as the mulberry.

However, the region and moist soil seem to contribute most to the duration [of the leaves]. For those that exist in dry and entirely thin places shed their leaves sooner, and the old ones do so before the new ones. Some also shed their leaves before they ripen their fruit, such as the late-bearing fig and wild pear trees. Occasions of setting and rising occur in turn for those that remain perpetually green. For they do not all last forever, but some grow while others wither. This seems to happen most around the summer solstice. Whether it happens in some regions even after the rising of Arcturus or otherwise is something to be left for consideration.

The falling of the leaves occurs in this way, but the leaves on all other trees are similar to themselves. The poplar, the ivy, and that which is called the croton a type of spurge or castor-oil plant have leaves that are dissimilar and possess a different shape. The new ones are rounded, while the old ones grow into an angle. In these, the transformation of all things is defined. But with the ivy, it is the opposite; for when it is new, it bears more angular leaves. When it has reached an advanced age, they are round, for it is also capable of having its leaves altered.

That is certainly peculiar which seems to happen to the olive, the linden, the elm, and the poplar. For they turn their upper surfaces shortly after the summer solstice, and by this sign, the country folk understand that the solstice is complete. All leaves differ from one another on the front and back parts, and the back part of the others is greener and smoother. They have nerves and veins on the front parts, just like hands. The back part of olive leaves, however, is whiter and less smooth. The ivy also has leaves that are smooth on the upper part, or at least most do; the back part hangs visibly and those are exposed to the sun, and for the most part, they turn toward the sun. Therefore, you would not easily say which part leans more toward the branch. Indeed, the turning over makes the closer part the front. But nature [does not].