Star Cactus
by Jim Seeden

          The star cactus is one of the most popular cacti with cactus collectors worldwide and the only known natural colonies in the world are here in Starr County.  A few years ago the Rio Grande Wilderness Society alerted The Nature Conservancy to the existence of a ranch, near Rio Grande City, which had a sizable number of star cacti.  Eventually, guided by the efforts of its representative Lisa Williams, TNC purchased the ranch and they now protect the world's only large colony of star cacti.  There are, fortunately, a few smaller colonies in Starr County, and efforts are underway to establish additional colonies.  Nonetheless, everyone lists the star cactus as an endangered species.

          Its scientific name is Astrophytum asterias and it's sometimes called sea urchin or sand dollar cactus.

          The reasons that star cacti are so popular are many.  It has a small, low dome, usually up to about 4" in diameter, 6" max, and a couple inches high, and can be easily grown in a pot.  It has no spines but has rows of gray, wooly tufts down the center of each of 8 segments.  The rather precise segments make the cactus look like a pie sliced into 8 even portions.  Each segment is speckled with rows of tiny, white dots called trichomes.  The blossoms, which are most numerous in the spring, are bright yellow with red-orange centers.  (The star cactus I grow, given to me by a friend whose ranch has a colony which was transplanted from another ranch which was being cleared, tends to bloom longer when watered regularly.)  It is indeed a very distinctive, attractive species, plus being exceedingly scarce.

          I should mention that hybridizers, using selective breeding, have created cultivars called Super Kabuto which have very large trichomes. 

          The cactus is usually a dull gray-green but turns rufous when in bright sun and stressed.  Also, when stressed, it shrinks to ground level and becomes well camouflaged.

          Its endangered rating results from at least four causes.  First, star cacti require very specific growing conditions including a heavy, saline soil type, preference for partial shade, and appropriate climate.  Second, during drought periods, animals, especially rabbits, eat them.  Third, unfortunately, humans poach them.  They're a valuable commodity.  What's worse, they look much like peyote and poachers looking for peyote dig the wrong species.  And fourth, loss of habitat as subdivisions, new roads, root-plowing and commercial expansion eliminate what few wild lands remain.  Once found in several Texas counties and northern Mexico, the star cactus is now limited to Starr County.
          At what appears to be increasing speed, many of the small wonders of our world are disappearing!  Please do what you can to support conservation efforts.

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