Tim,
Yes some of these have photosynthetic parenchyma on both sides of the leaves. The ones from subspecies hirta have the most wde-open rosettes whereas the ones from arenaria are mostly a ball.
Of course all of them fix CO2 by the CAM pathway so they accumulate malic acid at night and then utilize the carbon during the day when they can utilize the energy from the light reactions.
The rollers do not like my native soil that well but they LOVE the soil mix that I use in the raised beds.
Kevin
