Phylogenetic signal and climatic niche of stem photosynthesis in the mediterranean and desert regions of California and Baja California Peninsula.

Despite the fact that both photosynthetic stem types help cope with water shortage, having fleshy stems allows plants to cope with greater precipitation seasonality than is possible with green stems. Green stems require a lot of water to be stored in the soil to maintain net photosynthesis during the dry season, so they inhabit areas with higher and more predictable precipitation.