Many trees and other plants rely on associations with fungi to obtain the nutrients they need, in turn providing the fungi with energy. Some plants are able to tap into this fungal network without contributing anything themselves.
Pinesap is a generally uncommon plant found mostly in pine forests. The only reason this and similar species rise above the ground at all is to flower and produce seed.
The common Indian Pipe is very similar to Pinesap, but can be found in a wide variety of forests, even including wet treed bogs.
All orchids produce tiny seeds which rely on associations with fungi to germinate and grow for at least the early stages. Some species, like Spotted Coralroot, never develop green leaves at all.
Clump of Spotted Coralroot
Spotted Coralroot seedpods
Beechdrops parasitises trees directly, rather than only doing so through fungi like the species above. It is a well-named plant as it is only found in the vicinity of American Beech trees, and attaches directly to their roots.