Copiapoa humilis subsp. humilis (Philippi) Hutchison,
Cact. Succ. J. (US) 25(2):34 (1953)
Basionym: Echinocactus humilis Philippi, Flor. Atac. 23 (1860)

I have seen this taxon on the hills above Paposo. The area is particularly well known for its vegetation as the camanchaca mist is very dense in this region, which helps to support a rich flora. The distribution of C. humilis subsp. humilis appears to be quite restricted as collectors have recorded it only from the general vicinity of Paposo, from sea level (Graham Charles pers. comm.) up into the mountains to at least 700m in altitude. Evidence of guanaco (a wild relative to the llama) is commonplace and the ground is heavily disturbed by them rooting around for food. Guanaco eat the heads of the Copiapoa and most probably the roots too. However, if a portion of the tuber including basal parts of the stem survives, it will produce new heads.

Figure 2 The habitat of Copiapoa humilis subsp. humilis;
hills above Paposo, with camanchaca mists rolling in off the sea

They initially take on juvenile characteristics that are quite distinct from the adult form. Hutchison also reported that insect larvae consume the plant bodies and this may also encourage the growth of new heads from the roots. With time, untouched cultivated specimens will offset, although not as prolifically as when the primary head of plants the wild has been damaged or eaten. This subspecies has dark, purple-brown coloured bodies, slightly soft to the touch. The ribs are very indistinct with large rounded tubercles about 10mm across. Areoles bear a tuft of white wool, which is especially prevalent in the apex. Spines are dark, almost black, turning light grey in age. The juvenile heads are smaller in all their parts, with short spination lacking any centrals. Superficially they can look like a distinct miniature species, but as the plants mature the radial spines increase in length, centrals appear, and the plants can begin flowering at this stage. Radial spines are 8-12 in number, to 15mm long, and centrals up to 4, 25mm long. The flowers arise through the wool at the apex and are a rich yellow colour to approximately 5cm across. The root is large, tuberous and connected to the body by a thin neck consisting of stem tissue. I have grown plants in cultivation from seed which are necked but not excessively so. The extremely thin neck may only occur in old plants, perhaps when new heads are pushed up to the surface from an older rootstock after damage to the original plant bodies.

Figure 3 Copiapoa humilis subsp. humilis PM200(z),
seed raised cultivated plant showing juvenile and adult spination