Not sure how I missed this thread! It's a fun subject...even though I've read over a few articles and still have difficulty with the details of the process.
Here's a list of articles on the subject...not sure if you're only interested in reading up on orchids....
- Comparative Rates of Dark CO2 Uptake and Acidification in the Bromeliaceae, Orchidaceae and Euphorbiaceae
- Crassulacean Acid Metabolism and Its Possible Occurrence in the Plant Family Orchidacea
- Crassulacean Acid Metabolism in Australian Vascular Epiphytes and Some Related species
- Crassulacean Acid Metabolism in Orchids under Water Stress
- Crassulacean acid metabolism in the shade. Studies on an epiphytic fern, Pyrrosia longifolia, and other rainforest species from Australia.
- The Occurrence of Crassulacean Acid Metabolism Among Vascular Epiphytes From Central Panama
- Utilization and Dissipation of Absorbed Light Energy in the Epiphytic Crassulacean Acid Metabolism Bromeliad Tillandsia ionantha
My favorite article was easily "Crassulacean Acid Metabolism in Australian Vascular Epiphytes and Some Related species". It's been a while since I've read it but I think the authors noted a correlation between leaf thickness and CAM...with a few exceptions of course. What's interesting is while I was looking through a book on Australian Succulents I was surprised to find several orchids listed in the book.
PM me your e-mail address if you have difficulty finding any of the articles.