A species list of all known c4 plants as of 1971 (Hatch et al. 1971, Welkie & Caldwell, 1970) compiled by my friend Julie Kierstead and generously shared with me, lists 121 known monocot species with C4 photosynthesis compared to 174 known dicot species. I'm sorry, but I don't know how many of these dicots are woody. Peggy Pollak