The Living Rock cactus is an unusual cactus in many ways. For one thing, it is the only member of its genus living in the U.S. It lives only in the Trans-Pecos. It has no spines. It is toxic. It is usually almost-to-completely invisible, making it difficult to find during any time of the year outside of its blooming period. It flowers only in the fall. It has a taproot. It was recently the subject of a major bust of cattle rustlers who were caught with over 5000 plants stored in plastic bags.
It is extremely slow-growing, and outside of the small area around the Big Bend National Park, and Big Bend Ranch State Park, it is rare, even in its home territory. The above photograph shows one of these plants as it normally appear throughout the year. I have sharpened this image to make it easier to see.
Here in West Texas the plant is round, and rarely even an inch tall. When dry, its taproot shrinks and pulls the plant down, often until it is completely covered. The pointed “leaves” are tubercles. Each tubercle has a groove that widens towards the base which is covered with dull-colored trichomes. This image illustrates the plant more plainly than the first image.
Living Rock blooms from September to November. All flowers appear at the apex of the plant. They range from pink to magenta. Filaments are deep yellow with pale yellow to white styles and white stigma lobes.
Look for Living Rock cacti in rocky limestone or igneous soils. The plant does not tolerate gypsum well.
A ring of cactus thieves that stole over 5,000 of these plants was busted a few years ago. Thousands of these plant still live in the greenhouse at Sull Ross and are looking for homes. I’ve distributed over a hundred of them, but there are still many awaiting adoption. We hope that some may be returned to property owners from whom they were stolen in the first place!