So, which is the plant and which is the rock? Luckily for us, this Dioscorea mexicana, or Mexican yam, hasn’t gone deciduous for the summer. The juicy, thick, heart-shaped leaves are born along the single vine-like branch pushing up through the center of the caudex. The caudex resembles a turtle shell in my opinion, suggesting a common name for another species in the genus, turtle back (Dioscorea elephantipes (and if you’d like a challenge, spot the botanical terminology error in that fact sheet)).
I took this picture at Sherman Library and Gardens in Newport Beach, California. If you ever have a chance to visit this garden, please do! It’s a beautiful little place The cactus and succulent garden is incredible in its species diversity, specimen quality, and design (not to mention the hand-harvested boulders and minerals).
This Dioscorea is native from northeast Mexico south to Panama. The part of the plant that looks like a turtle shell is called a caudex (hence, it is a caudiciform plant). This massive storage unit helps the Mexican yam to survive a range of temperatures and habitats, including arid rocky outcrops.