The cactus genus Copiapoa is endemic entirely to the nation of Chile, which contains somewhere between 29 and 37 different species and subspecies depending upon who’s doing the ranking. They grow in a range of habitats from hyperarid coastal Atacama Desert to montane Andean valleys and even into the borderlands where desert merges into more densely-vegetated matorral (a xeric shrubland akin to chaparral and other Mediterranean climates.) The majority of species are from the coastal regions of the Atacama Desert in the central and northern parts of the country.

It’s pretty easy to love Copiapoas. They are handsome, charismatic, shapely, and some species grow into impressively large clumps in an extremely rigorous environment. There’s a romance to traveling their remote and sparsely populated habitat, with its soaring cliff faces plunging into the ocean and the dense fog (called camanchaca in Chile) that dominates the weather. In dry years, which is most of the time actually, they are often the primary and sometimes the only plants above ground, although in rare wet years they can be joined by dozens of wildflowers that emerge from the barren soil as if by magic. Many have been captivated by Copiapoas, myself included.

In October 2017 I took advantage of one of those wet years to go to Chile and see many of the different species in conjunction with the wildflower show known as El Desierto Florido. I ended up seeing somewhere around 15 different species, including many of the most dramatic. One such wonderful day of cactus exploration was on the stretch of highway between the Chilean towns of Taltal and Paposo, where at least five different taxa were seen, with arguably a sixth as well. Here are a small sampling of images showing each species in just one photo. Each one merits an entire blog post of its own, which I hope I will find time to create in the future, but this sampler platter will suffice as an introduction for now.  

Beauty and the Beast

The first Copiapoa find of the day was this species: Copiapoa cinerea from Taltal, Chile way high up a foggy mountain, found with the pink flowering bulb Rhodophiala laeta, another new species I’d never seen outside of online images. What a distinctive pairing!

Species two of the day: Copiapoa albispina. The crested portion made this one of the single coolest plant finds of the day, adding extra interest to an already gorgeous species on a botanically productive day.

One of the notable features of many Copiapoas is the white “snowcapped” look, which is due to a wax layer that conserves water and reflects sun. The wax is secreted from specialized epidermal glands and coats the outermost skin, and helps greatly retard the loss of water. Ironically, despite the near total absence of rain year-round, the humidity is always high this close to the foggy Pacific Ocean, and in between the low evapotranspiration rates and the waxiness, this makes Copiapoas masters at holding onto whatever small amount of rainfall (or even heavy dew) they glean from the environment. In a place where up to two or three years may pass without any rainfall at all (just fog and dew condensation) this adds a useful margin of survival. The pale coloration also reflects sunlight, which aids in water conservation. It does tend to wear off after some years, leaving the corky-looking brownish epidermal cells of the older basal stems exposed and polished to a semi-glossy sheen.

Species three of the Day of Copiapoas: When C. gigantea steals your hat!

Species four: Copiapoa haseltoniana, a truly beautiful plant. It makes me salivate. It’s sort of messy and embarrassing, actually.

Fifth and final species of the day: Copiapoa eremophila looking mighty fine, wedged in amongst the tortured rocks of the Chilean coastline. This makes for at least 11 or 12 Copiapoa species I’ve seen thus far. Can you all see why people fall in love with this genus?

Bonus species, a transitional one between two already seen, bringing the total to six, sort of….

This is what our reference guide book called the transitional form between Copiapoa gigantea and C. haseltoniana, which appears to be intermediate between the two. It’s not a full on species to either one, nor is it a hybrid, because all of the plants are similar in this population, without either of the two “parents” present, making it occupy a shifting spot on the genetic tree of life.
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All of these Copiapoas show clear similarities of growth form and general character, yet individual plants can admittedly be challenging to place precisely without DNA analysis. (And even then it might still be difficult.) The spectrum of morphology amongst these five species and one transitional form over the span of about 100 miles shows in microcosm how evolution operates over time. The extremely narrow coastal bench of Chile in this region is the only habitat suitable for these cacti and all other plants, and it is because of the nearby ocean and banks of persistent fog that this is so. Inland not more than 5 to 10 miles, the fog is gone, rain almost never happens, and the landscape is truly best described as “barren” in the most literal sense of the word. Not a single sprout of green can be seen in the high, dry, and fog-free inland regions of the Atacama just east of here, some portions of which have not seen rain in hundreds of years, possibly thousands.

This dynamic means that Copiapoa populations are extremely genetically isolated. There are few pollinators present in dry years and only a bare minimum more in a “wet” one, and most of them are small bees or flies with limited mobility, short flying ranges, and little incentive or need to fly laterally up and down the steep, rocky coastline. Especially not with strong inland crosswinds that might blow them eastwards into the truly rainless deserts to die. These geographic and meteorological barriers to north-south insect migration mean that insects tend to stay put within a few hundred meters of existing Copiapoa populations, which are themselves discontinuous, and thus gene flow of the plants is restricted up and down the coastline as well.

It is in this way that borderline inbreeding within narrow and isolated population clusters will over generations tend to give rise to unique forms of plants, insects, and small animals. This type of evolutionary process is well documented and easily observed in how terrestrial species colonize various islands separated by wide swaths of water in an archipelago itself isolated by thousands of miles of ocean. (The Hawaiian Islands, and most famously the Galapagos Islands, are among the best known examples of this.) And indeed the narrow valleys of fog-sustained life in the northern Atacama Desert of Chile follow this same archipelago pattern, isolated as they are by ocean to the west and the world’s most extreme desert to the east. This isolation leads to genetic drift and the formation of new species in the same way that Darwin’s Galapagos finches or Hawaiian honeycreepers did. With Chile, it’s Copiapoa cacti.

And with this, I must go to bed. I never sleep enough on these trips. While extremely rewarding, they are seldom “relaxing” because of the long days and rigorous schedules we keep in order to bring you these images. Enjoy!