For a plant to eek out a living in the rockies requires a lot of adaptations. With cold temperatures and harsh winds throughout much of the year, they must find suitable micro-climates that can support them. The winds bring with it just enough dust that settles out over time in any nook, including rock crevices. This creates a foothold for the shallow roots, while the small lip in the rock shelters the plant from the harsh winds, radiates the heat from the sun back onto the plant and funnels water to the roots.  A perfect spot for a miniature plant.