Excerpts from Jim Conrad's
from the the June 7, 2009 Newsletter, issued from the Siskiyou Mountains west of Grants Pass, Oregon:
On a large serpentine boulder down in the moist, sheltered valley below where I'm staying the Broadleaf Stonecrop, SEDUM SPATHULIFOLIUM, is in flower. That's it above.
You can understand why succulents often are found on boulders. When it rains, water runs off quickly and desert conditions on the boulder's surface return. Succulents soak up rainwater very fast and store it in their thick, succulent stems and leaves.
Similar stonecrop species occupy similar ecological niches in the East, but this is a different species, distributed in the mountains from British Columbia through the Pacific coast states to southern California.