Humans always assume intelligence requires a brain. I think sugar cane are quite intelligent on the other hand. They have came up with a means to coopt another species for breeding: us humans, who have in turn created this cult of the sugar cane where it is now the most cultivated crop on the planet for probably the forseeable future. What an amazingly efficient way to proliferate your lineage. You don’t need to evolve these costly and highly derived structures like brains or articulated thumbs yourself, let the dumb human break their back harvesting you and spreading your lineage around the world.

Totally. Between bread and alcohol, yeast has basically managed to domesticate humans. Maybe our experiences differ so much that we can't strike up a conversion, but that's no reason to discount intelligence.