The Portuguese, perhaps more than the Spaniards, seem to have brought home a lot of vegetable species in the Age of Discoveries.
Hence both the botanical Gardens and the well-known estufas have quite a heavy South American leaning.
The Botanical Gardens are attached to the University and there are some interesting exhibitin pavilions inside but the real pleasure is to wander downhill to the bottom exit - not an entrance!
The Estufas also contain a small outdoor area with oriental birds.