Lophocereus marginatus

Lophocereus marginatus is a species of plant in the family Cactaceae. It is sometimes called Mexican fencepost cactus.

Description
It has tree-shaped columnar trunks that grow slowly to 12 ft and may reach 20 ft in height, rarely branching. Stems are 3 to 4 in in diameter, with ribs 4 to 7 in. Its central spine is about 3/8 in in diameter with five to 9 radials and slightly yellowish in color. The five to nine marginal spines are 2 to 4 millimeters long. The large areoles on it later merge. The flowering areoles located near the shoot tips are covered with numerous bristles up to 2 centimeters long.

The funnel-shaped, reddish flowers are 3 to 4 centimeters long. Their pericarpel and floral tube are covered with scales that carry wool and bristles in their axils. The spherical fruits are more or less dry. They reach a diameter of up to 4 centimeters and are covered with slightly sloping thorns and wool.

Its cuttings are sometimes used to create fences, as its spines are not as large or dangerous as some cacti.

Distribution
The species is native to Mexico states of Hidalgo, México, Guanajuato, Querétaro, Morelos, Puebla, Oaxaca, Colima, Michoacán and Guerrero. It is also found in U.S. states that border Mexico: Texas, New Mexico, Arizona, and Southern California.

Taxonomy
The first description as Cereus marginatus was made in 1828 by Augustin-Pyrame de Candolle. The specific epithet marginatus comes from Latin, means 'bordered' and refers to the 'edges' formed by the areoles that flow together on the ribs. Salvador Arias and Teresa Terrazas placed the species in the genus Lophocereus in 2009. Further nomenclature synonyms are Pachycereus marginatus (DC.) Britton & Rose (1909), Lemaireocereus marginatus (DC.) A.Berger (1929), Marginatocereus marginatus (DC.) Backeb. (1942) and Stenocereus marginatus (DC.) A.Berger & Buxb. (1961).