Some inspiring Resource From the website of Virginia Sasser
Plant Anatomy
Set of “scientific” lettering studies, drawn from microscopic anatomical cross-sections of each: Seed, Root, and Leaf.
http://cargocollective.com/ginsasser/Plant-Anatomy
http://cargocollective.com/ginsasser/Rhetorical-Chairs
“How to Get Ideas” chapter of Graphic Design Thinking: Beyond Brainstorming, ed. Ellen Lupton (Princeton Architectural Press, 2011).