My impression is that all this information is scattered through different references, I have seen many devoted to some families, subfamilies and genus (example attached), but I wonder if this evidence has been compiled systematically somewhere.
Hi Antoine, I worked on epiphytic plants that are either C3 or CAM. You can get a partial listing in this book. I've also attached the book chapter for your reference. Hope it is useful for you? Best wishes, John.
Book The Physiology Of Tropical Orchids In Relation To The Industry
In addition to the book mentioned by Antoine (a very good monograph work), you can also see: 1. A revised list of the European C4 plants - I. Mateu Andres, Photosynthetica, 26 (3), 1993, p. 323-331 and 2. Micro-ecology and some related aspects of C4 plants living in Europe - I. Mateu Andres, Photosynthetica, 29 (4), 1993, p. 583-594.
There are also many papers focused on C4 photosynthesis especially in Chenopodiaceae/Amaranthaceae, where you can find lists with plant species, evolutionary aspects and ecological significance of this photosynthetic pathway.
again a couple of references which might help pinpoint a few genera:
1. Pyankov VI, Gunin PD, Tsoog S, Black CC (2000) C-4 plants in the vegetation of Mongolia: their natural occurrence and geographical distribution in relation to climate. Oecologia 123, 15–31. doi:10.1007/s004420050985
2. Zotz G, Ziegler H (1997) The occurrence of crassulacean metabolism among vascular epiphytes from central Panama. New Phytologist 137, 223–229.
I'm not sure whether you're still interested in this question but here's a fantastic resource, near to complete for all grasses: http://onlinelibrary.wiley.com/doi/10.1111/nph.12942/abstract