In a recent conversation with several friends regarding ba'alei teshuva marrying Kohanim (specifically college students), one person present said that a Kohen can only marry a virgin. I contested this point based on the first Aliyah of Parshat Emor. Plus, I remember at least one explanation that said a regular Kohen can marry a widow, but cannot marry a divorcee. However, that same person says the prohibition for a regular Kohen is derived from the Kohen Gadol.
So, is a regular Kohen allowed to marry a widow or is he - like the Kohen Gadol - required to only marry a virgin?