Foreign plants, often weeds, rushed onto the bare lands where forests once stood. Most of the plant pests of the Canaries have come from the mainlands, especially from southern Europe and North Africa. Only two on a list of the Canaries’ worst plant pests now are natives. Perhaps the worst of the weeds is the Mediterranean bramble or blackberry, Rubus ulmifolius. It may or may not be prehispanic in these islands, but there is no doubt as to its origin — the Mediterranean littoral — nor to the fact that since the conquest it has spread like a plague over the traumatized lands of the Canaries.59