Trusted digital libraries (Project Gutenberg, Open Library).
Look for ethnobotany textbooks. Titles like:
If you're a student or scholar, access peer-reviewed articles and book chapters via:
Because much of this knowledge was historically passed down orally, finding a definitive version can be tricky. However, several digital archives host versions of these "pocket notes" and guides. Buka Ya Dingaka | PDF - Scribd