Corn C4 Photosynthesis

Is corn an obligate C4 plant?


Edit: A corollary to the above question is where does the majority of photosynthesis occur in corn?

This page makes it sounds as if C4 photosynthesis is only used as a supplementary pathway and C3 photosynthesis can still be used (some plants, such as cacti, do use a third form known as crassulacean acid metabolism, and some are obligate in that regard):

(emphasis theirs)

As for which parts of the plant are responsible for photosynthesis, it would be the leaves and stem, pretty much any green part (yes, stems can photosynthesize too as this source says; “Plant photosynthesis occurs in leaves and green stems”, but probably a relatively minor contributor except for cacti and similar plants).