''Cereus mortensenii'' is a species of plant found in Venezuela. It is the only ''Cereus'' species with a

cephalium A Cephalium is generally defined as the dimorphism between Sexually mature and immature cacti, often with the confluence of areoles, production of hairs, or periderm development at or underneath the areoles after flowering. The area of which dense ...

Description

''Cereus mortensenii'' is a treelike plant, growing up to tall. The bluish stems are up to wide and have woolly

areoles In botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. Gordon Rowley - Wh ...

. Each areole has 1 or 2 central spines up to long and 5-7 radial spine up to long. Cream colored flowers up to long emerge from the white cephalium on mature plants.

Taxonomy

This plant is sometimes placed in the genus

Pilosocereus ''Pilosocereus'' (from Latin, "hairy cereus") is a genus of cactus native to the Neotropics. Tree cactus is a common name for ''Pilosocereus'' species. The genera ''Caerulocereus'' and ''Pseudopilocereus'' are synonyms of this genus. The commonl ...

because of its cephalium.

etymology

This plant is named for Russell H. Mortensen who helped with the discovery and collection of this species

References

{{Taxonbar, from=Q1055146 mortensenii Flora of Venezuela Cacti of South America