Copiapoa humilis form from Guanillos

In 1971 Alfred Lau discovered the smallest growing Copiapoa species, C. laui, in the Guanillos valley just to the north of Esmeralda (clearly marked on many maps, although now just an abandoned mine). This is an amazingly rich area for Copiapoa, with five distinct taxa growing in close proximity. Cactus enthusiasts who have visited the area since then have found, growing in association with Copiapoa laui, another small Copiapoa belonging to the C. humilis complex. It has been misidentified by many authors as Ritter’s C. esmeraldana but I believe that to be incorrect (see Copiapoa grandiflora subsp. ritteri below). That leaves the C. humilis form in the Guanillos valley north of Esmeralda without a valid name. I have seen this plant on low hills where they grow flat against the ground in grit. The epidermis is light brown-coloured, with a hint of a waxy coating. They grow as solitary specimens or occasionally as small clumps. The spination can be quite variable and almost absent in many specimens.

Strongly spined specimens have 6-8 radials and 3-5 central spines. The flower is smaller than the type being 20mm or less across but with a very pronounced red colour on the outside of the petals, so developing buds look red.

I believe that this taxon requires a name, as it is quite distinct from C. humilis subsp. humilis, with different habitat preference, body shape and colour, short or absent spination and a smaller flower. Seedlings grown in cultivation appear to retain these characteristics.

Unfortunately, due to the lack of a type specimen,  I cannot validly describe this plant at this time.

Figure 18 The habitat of Copiapoa humilis from Guanillos
a grit covered hill (Esmeralda 300m)