Echinopsis mamillosa

Echinopsis mamillosa is a species of cactus from Bolivia.
Description.
"Echinopsis mamillosa" has a solitary growth habit, with globe-shaped stems up to tall. The stems are dark green, with a diameter of up across, and have 13–17 deep ribs, formed into tubercles. The rounded areoles are spaced up to and produce yellowish spines with brown tips, the one to four central spines being up to long and the 8–12 radial spines long. The flowers are white with rose tips. They are large in relation to the diameter of the stems, up to across and long.
Two subspecies are recognized. Subspecies "mamillosa" is shorter (typically only up to tall) with 17 ribs. Subspecies "silvatica" is taller and has fewer ribs.
Taxonomy.
"Echinopsis mamillosa" was first described in 1907 by the German botanist Max Gürke. "E. silvatica" was included in "E. mamillosa" as the subspecies "silvatica" by Pierre Braun and E. Esteves Pereira in 1995. The circumscription of "Echinopsis" remains controversial; the genus is accepted not to be monophyletic.