Copiapoa megarhiza

Copiapoa megarhiza is a very spiny species of cactus with a solitary or somewhat-branched stem. Its growth form is globose to somewhat elongated, and it is gray-green in color. It measures 10-25 cm in length and 7-10 cm in diameter. Its apex is covered in gray woolly trichomes, and its taproot is large and tuberous.

This species has 13-17 ribs which are divided into tubercles and slightly widened around the areoles. The areoles are rounded to oval in shape and measure 0.4-0.7 cm in diameter. These have thick spines that are yellow to black in color but turn gray with age. Among these, there are up to 4 especially thick central spines which range from straight to curved and measure up to 4 cm in length. There are also 8-10 somewhat-curved radial spines, which measure up to 3 cm in length.

The flowers are funnel-shaped and yellow in color, measuring up to 3 cm in length. The fruits are olive green in color and egg-shaped, measuring up to 1.5 cm in diameter. They have many wide, fleshy scales near their margins, and some on their lower parts. Inside, the seeds are black and shiny.

Copiapoa megarhiza is native to the Atacama Desert in northern Chile, where it is found in desert or dry scrubland biomes at altitudes of 0 to 800 m above sea level. It grows in alluvial soils and on rocky, north-facing slopes.

This species is cultivated mainly as an ornamental. It may be propagated vegetatively via cuttings, or via seed.