In this trail, you can see one of the most emblematic tree species in Galicia: oak (Quercus robur). This tree, is distributed throughout much of Europe, Asia and North Africa, and it is one of the most characteristic species of the Atlantic forest. Many stories have been woven in his shadow.
It is easily distinguished by its leaves, which have a very short petiole and deeply lobed edges that are unequal and rounded. The leaves are hairless. Its fruits are acorns and hang from the branches on a long peduncle. Keep these characteristics, because they will help you to be an expert botanical and to easily identify this beautiful tree!
Along the trail, you will see that in many oaks appear spherical excrescences that seem fruits. They are not! They are galls, spherical structures similar to a tumor produced by the tree itself as a defense reaction against eggs that put small wasps under the bark. However, this defense structures created by the tree serve as a shelter and food for wasp larvae. In their interior, they are protected from adverse environmental conditions and grow by absorbing the nutritive tissues.
The reproductive system of this plant is peculiar. It is worth to understand it! Male and female gametes occur in the same tree, but in separate and distinct flowers, because the species is monoecious. The fruits of this tree are produced by wind pollination: when the male gametes are transported by the wind to a female flower, fertilize the ovule and the fertilized flower is transformed into an acorn.