Clement of Alexandria

The graft uses as soil the tree in which it is engrafted. Now all the plants sprouted forth simultaneously in consequence of the divine order. Wherefore also, though the wild olive is wild, it crowns the Olympic victors.… Now we see that the wild trees attract more nutriment because they cannot ripen. The wild trees therefore have less power of secretion than those that are cultivated. And the cause of their wildness is the absence of the power of secretion. The engrafted olive accordingly receives more nutriment from its growing in the cultivated one, and it gets accustomed, as it were, to secrete the nutriment, becoming thus assimilated to the fatness of the cultivated tree.