Copiapoa rarissima is a small, slow-growing cactus endemic to a tiny area of coastal Chile. This critically endangered species is characterized by its globular, gray-green stems, often solitary or forming small clusters. The prominent ribs are adorned with woolly areoles, from which emerge short, black spines. Copiapoa rarissima produces stunning yellow flowers, a rare sight in cultivation due to its specific care requirements and conservation status.