Seasonal Poetry in Sanskrit : The blog Sanskrit Literature has been running an excellent series on plants that appear in sanskrit poetry. Some examples : Jasmine (malati), Lotuses and Water Lilies, Mango.
Botanical Drawings for the Digital Age "Macoto Murayama can spend months on one of his botanical illustrations, and when he’s done, the plant looks like something that blossomed in outer space."
The Mathematical Lives of Plants "Scientists have puzzled over this pattern of plant growth for hundreds of years. Why would plants prefer the golden angle to any other? And how can plants possibly "know" anything about Fibonacci numbers?"
A xylothek is literally a library of wood, a collection of book-like boxes made from trees--the wood and bark with the seeds, leaves, flowers, fruit--or illustrations of the soft parts (site in German), inside.