There are an interesting selection of flowering plants that do not depend on their own root systems and photosynthesis to generate the essential elements they need, they attach themselves to other plants and drain what they need from them. Others are even more curious in that they catch and consume insects for their nutrients. Whilst not related I think they make for an interesting book as a group.
Tap/click the icon to open the book and start reading. There is one species per page and you can swipe right to page forward and swipe left to go back (arrows are provided for those without a touch screen).