CactiGuide.com

I see two widely different pictures at this entry, they seem like 2 different species. You can see the parts of a different cactus on the top image which may be the same as the bottom one.

Copiapoa's in general are extremely variable and the same specie can look quite different from each other.

In this case (as with alot of other types of cacti) a young seedling can look nothing like a mature specimen.

That is a good point. As you look around, you will see a lot more of that. Most of the time here you are seeing the maddening variation of cacti "species" that makes ID so very difficult.

Sometimes you are seeing a genuine error. I'm pretty sure these ID's are accurate based on the sources.

Here is one of the best examples of the mind-blowing differences that may be due to age, environment, population, etc...

http://www.cactiguide.com/cactus/?genus ... ies=aurata

Copiapoas are often mis-named. Equally they are so variable that correctly tagged plants look as if they are mis-named One obvious variation is that juvenile plants tend to be tubercular and adults develop ribs. They may also grow stronger spines as they mature, occasionally lose most of their spines, or even fail to grow into a mature form at all. Body and spine colour may change as the plant ages, usually the youngsters being more strongly coloured while the adults tend towards green bodies (sometimes with a white coating) and grey spines.

Copiapoa atacamensis is a name which is subject to a variety of confusions, but is now considered to be a subspecies of C. calderana. I find the plants to be very similar although from very different areas. C. calderana ssp calderana often has very dark bodies in juvenile form while I haven't seen this for ssp atacamensis.

See these habitat photos for examples of what the plant grows into given enough time.