Living Rocks, Golf Balls, and Other Strangely Named Cacti of the Trans-Pecos.


Living Rock Cactus

Target Species:

Black-tailed Rattlesnake (Crotalus ornatus)

Button Cactus (Epithelantha micromeris)

Lacespine Nipple Cactus (Mammillaria lasiacantha)

Living Rock Cactus (Ariocarpus fissuratus)

The landscape of Big Bend is striking for its vastness; famous for its sweeping views that stretch from horizon to horizon, and seemingly beyond.  Stepping into this rugged wilderness, one is immediately hit with the harshness of this land.  Brutal conditions created by lack of rainfall and extreme temperatures.  It is easy to think that this seemingly inhospitable land  would be devoid of life, but despite its harshness it is incredibly diverse, harboring a rich flora and fauna unlike anywhere else on the planet.  And as remarkable as this vastness is, equally astounding is the beauty and variety that can be found in just one small patch of the desert floor.

Big Bend, that large peninsula of Texas that dips down into Mexico as it follow a bend in the Rio Grande, has the greatest cactus diversity in the country.  It was that diversity that brought Carolina and I to the region this October.  Specifically we were hoping to find the Living Rock Cactus (Ariocarpus fissuratus) in bloom.

Big Bend is part of the Chihuahuan Desert.  It is the highest, wettest desert in North America, and the most biodiverse in the world.  The Big Bend Region includes a multitude of natural and cultural attractions, including Big Bend National Park, Big Bend Ranch State Park, and Terlingua.  We planned to explore these areas in pursuit of our succulent quarries, and hoped that our pursuit would bring with it other natural wonders.

Cactus hunting is not without its hazards.  Aside from the obvious risk of an errant spine in the skin, there are other denizens of cactus country that pack a punch.  One such inhabitant is the Black-tailed Rattlesnake (Crotalus ornatus).  Yet despite this creatures fearsome reputation as a venomous marauder, it is one of the most docile snake species I have had the good fortune to encounter.

As I scoured a rock cut in search of spiny succulents, my eyes caught a familiar outline – a striking (as in attractive) Crotalus ornatus coiled at the mouth of a deep crevice in the limestone.  It was sitting, I presumed, waiting for some unsuspecting rodent to wander within its grasp.  Generally speaking, I think that the threat of rattlesnakes to your average desert-goer is greatly exaggerated, however seeing this beauty hidden away in the perfect hand or foot hold certainly reinforced the old adage “look before you step”.  The photo below depicts the animal as I found it.


Black-tailed Rattlesnake

After spending a few moments with the black-tail I continued my search for cacti.  After a moment I heard Carolina call out that she had found something.  How she spotted them, I’ll never know, but she had found a population of the diminutive Button Cactus (Epithelantha micromeris).  This diminutive cactus seldom protrudes more than 2 inches above the rocky substrate it calls home.  It occurs primarily in Mexico, but also throughout much of West Texas, southern New Mexico, and extreme southeastern Arizona.

Though they were not in flower, I found these small, rock-like cacti to be quite photogenic.  They flower primarily in late winter and early spring.  Later in the year an elongated red fruit appears.  Caro likened the fruit to a particular part of an excited dog’s anatomy.


Button Cactus


Button Cactus

Nestled in a few populations along the Pecos/Brewster County line, one may find a particularly formidable looking cactus.  The Icicle Cholla (Cylindropuntia tunicata) is a wide ranging species, occurring in deserts throughout much of Latin America.  In the United States, however, it is known only from these few places in the Trans-Pecos of Texas.  Admiring the afternoon light filtering through its intimidating spines, it was easy to see how it earned its common name.


Icicle Cactus

After a long day of travelling and exploring we finally made it to Marathon, but not before stopping at an extensive Black-tailed Prairie Dog town, where we admired their antics as the day began to fade.  We made our camp in Marathon, and I found myself deep in thought as we laid in our sleeping bags looking up at the twinkling wonder of space.  Along with the prerequisite existential questions inspired by such a vista, I pondered on the days to come, and the natural wonders that awaited us.

The next morning I spotted a remarkable creature on the stucco outside the campground’s bathrooms.  It was a male Chihuahuan Agapema (Agapema dyari).  A lovely member of the giant silkmoth family (Saturniidae).  I gently moved it to a nearby tree trunk, where I hoped it would be less obvious to the hoard of House Sparrows that were scouring the area.


Chihuahuan Agapema

As the sun warmed the desert we broke our condensation-laden camp and set out for Big Bend National Park.  As we crossed into the park we immediately took notice of the diverse cactus community.  The most obvious were the abundant clumps of Strawberry Cactus (Echinocereus stramineus), the heavily armed Eagle’s Claw Cactus (Echinocactus horizonthalonius), and the ubiquitous prickly pears (Opuntia spp.).

Finding the smaller, more cryptic species, took a bit more work.  We found the Lacespine Nipple Cactus (Mammillaria lasiacantha) to be quite common.  Also known as the Golf Ball Cactus, this tiny succulent is quite similar to the Button Cactus.  Cacti of Texas, A Field Guide by Powell, et. al discusses some of the differences.


Lacespine Nipple Cactus

The real reason for our trip, however, was to try to catch the Living Rock Cactus (Ariocarpus fissuratus) in bloom.  This bizarre cactus is, in my opinion, one of the most spectacular plants in the country.  Hardly recognizable as a cactus, it is spineless, and consists of rough tubercles arranged in concentric rings around a center of soft fuzz.

For most of the year the dull green to gray Living Rock blends perfectly with the scattered stones that litter its limestone home, relying on camouflage rather than piercing spines for defense.  For a few short weeks in the fall, however, the limestone hills of the Trans-Pecos explode with color as thousands upon thousands of Living Rocks open their bright pink blooms to the world.

It was just such a scene that I was hoping Carolina and I would encounter in Big Bend.  We were soon to find, however, that finding these jewels of the Chihuahuan Desert in bloom would be far more difficult than we anticipated.  We spent all day scouring limestone ridges, bluffs along the Rio Grande, and flats in the low desert.  We jumped for joy when we found our first plant.  We knew we were were in the right area.  Even without their blooms, the Living Rock is a beautiful, bizarre plant and photographic subject.


Living Rock Cactus

The desert sun is relentless, even in mid October.  Our spirits refreshed by finding our first Living Rock, we pushed on, scouring the bleached white limestone hills as the temperatures flirted with 100 degrees.  It was truly brutal, but we knew that the payoff of seeing the blooms would be well worth our suffering.  After several hours, and several hundred more Living Rocks sighted, however, the blooms did not come.  We were dismayed.  We had become proficient at spotting the near invisible cacti on the desert floor, but despite finding so many individuals in several different areas, we did not find a single bloom.  I began to think that this would not be the trip that we would see the exquisite flowers of Ariocarpus fissuratus.


Living Rock Cactus

That night we hoped to camp in the park, but alas, all of the campgrounds were full.  We debated between staying at a primitive campsite along a backcountry road, or driving to the campground in Study Butte.  In the end we opted for the latter, and made the drive from the Rio Grande to Study Butte in the darkness, with nothing but the Common Poorwhills, Black-tailed Jackrabbits, and Western Diamondbacks to keep us company.

When we arrived at the campground, the attendant informed us that there was a party going on that would last well into the night, and recommended that we select a site on the other  side of the property.  We happily agreed.  We made camp, ate dinner, and settled in for the evening.  The “party” turned out to be a music festival that blared across the desert until after 1 am, after which the multitude of bikers attending continued to keep us awake for at least another hour.  Finally, at some point in the wee hours before dawn we drifted off.

We were awoken around 6 am to gale force wind violently shaking our tent.  The temperature had dropped by tens of degrees, and as we stepped out from behind the nylon the air met us with a chill.  I must admit, as I broke camp with powerful wind gusts and stinging dust beating down on me, I was hating life.  “Not every trip can be a success,” I reminded myself, and I tried to take solace in the incredible organisms we had thusfar encountered, and the memories we had created.  In that moment, however, it was hard to do.

We decided to spend the morning and early afternoon exploring the area, before beginning our long journey back to the Pineywoods.  The habitat at our first stop looked promising, but after a lack of blooms the previous day, I took care not to get my hopes up.  We soon saw our first Living Rock, like a star etched into the talus.  I found myself once again admiring their bizarre firm when I heard Carolina shout out in glee.  I knew.  The memory of the brutal previous night faded as I made my way to her, and saw the bright pink bloom seemingly emerging from nothing.  We did it.  It was not long before we found another, and another.


Living Rock Cactus

The Living Rock is one of three spineless cacti in Texas.  Their lack of spines means that they must rely on camouflage to avoid predation.  They also contain foul-tasting alkaloids which likely deter would be predators.  These alkaloids, however, have made this plant popular with the Tarahumara and other early tribes and settlers.  Though they do not contain mescaline like the similarly spineless Peyote, they contain other mildly hallucinogenic compounds like hordenine, and were reportedly used as a substitute when preferable psychoactive cacti weren’t available.  Hordenine also made the Living Rock useful for a number of medicinal purposes, including a disinfectant for wounds and burns.


Living Rock Cactus

Ariocarpus fissuratus is  endemic to the Chihuahuan Desert.  They barely enter the U.S. in West Texas.  They are incredibly tough, even for a cactus.  We found that they would grow in the harshest parts of the landscape, often where even other succulents could not survive.  They owe their success to their uncanny capacity to store water, and their ability to shrivel away to virtually nothing in times of extreme drought.  Indeed, they often times seem to be more stone than plant.  Carolina and I admired them for some time, and reluctantly bid them farewell, content with the short moment in time we were fortunate enough to spend among their fleeting blooms.


Living Rock Cactus

There are some songs that serve to inspire us and remind of of those things in this world that are most important to us.  For me, one such song is Stubborn Love by the Lumineers, and it came up on the playlist just as the Chisos Mountains began to fade in our rearview.  I looked about the desert that stretched beyond the horizons around us, and I was filled with a sense of contentment.  It’s easy to feel sad at the end of a great trip, but I take comfort in the fact that no matter where I am, if nature is near there is some great wonder waiting to be discovered.