Complex sentence: The northern (low elevation) sector has many species of Guineo-Congolian flora, including two endangered species, the brown mahogany and "Brazzeia longipedicellata".
Split into simpler sentences: The northern (low altitude) sector has many species of the Guineo-Congolian flora. These include two species internationally recognised as endangered, the brown mahogany and "Brazzeia longipedicellata".