I had a Purple Monkshood in my inventory. Since this was my first of that type I wanted to keep it and spared it (usually I always put them into my shop prior to giving away flowers), when giving away flowers. However, (I did check every single page) a different flower was eventually left in my inventory.

I gave them all but this one - all that showed on the page "Which flower would you like to give", yet it was gone afterwards and another one remained in my inventory. Utterly weird.