Flipping the usual script, where mycorrhizal fungi siphon sugar from plant roots, some plants get all or part of their food from parasitism upon those fungi (who probably got it from trees), rather than from photosynthesis.

The pyrola group is one of a select few that can live both photosynthetically or not.

The plants on this list are known or likely mycorrhizal cheaters at Sagehen. They are typically found in the shade, which explains a lot.

More info.