I also have the same book Lori mentions. It's excellent!
Do remember that there are many botanical terms that
seem the same, but individual meanings are separate.
---- For instance, pubescent, tomentose, strigose, hirsute, hispid, canescent, wooly, lanate: they all mean "hairy" to some degree. But each has a particular twist on the description that is necessary for accurate botanical description. Understanding these subtleties can be critical when using plant ID keys.
---- So having just a thesaurus list of similar botanical words would be very misleading, unless one could somehow know the differences between the listed words. That's where a glossary like the aforementioned
Plant Identification Terminology: An Illustrated Glossary comes in handy.
Now a Botanical-English Thesaurus/English-Botanical Dictionary, that would be pretty cool. One could then look up the word "white" in the English-Botanical part, see the related botanical terms, and then cross-reference those words in the Botanical-English part to see which botanical term for "white" is most appropriate for the purpose.
As close to this as I know would still be the same plant identification terminology book previously mentioned. It has separate sections devoted to parts of the plant, like leaves, surfaces, stems, roots or flowers. You wouldn't have to read the whole book to look for words that mean "smooth", for example.
