Submitted by: Jim Tanner

North American Columnar Cacti are this month’s Plant of the Month. Columnar cacti belong to the Cactaceae family, and consist of erect, cylinder-shaped stems, which may or may not branch, without a very clear division into trunk and branches. They have ribs and spines which run vertically along their length with great variation in spacing of ribs and number of spines.

Some cacti may become tree-sized but without branches, such as larger specimens of Echinocactus platyacanthus. Cacti may also be described as shrubby, with several stems coming from the ground or from branches very low down, such as in Stenocereus thurberi.
Cacti that are smaller than the tree-like (arborescent) ones may be described as columnar. The boundary between columnar forms and tree-like or shrubby forms is difficult to define. Smaller and younger specimens of Cephalocereus senilis, for example, are columnar, whereas older and larger specimens may become tree-like. In some cases, the “columns” may be horizontal rather than vertical. For example, Stenocereus eruca has stems growing horizontally along the ground, rooting at intervals.

Columnar cacti are important sources of food and shelter for many desert animals. Their flowers produce nectar and pollen for pollinators, and their fruits provide food for animals. Birds make holes in saguaros for nesting, and great horned owls and red-tailed hawks build nests in the cacti’s arms.

In cultivation, columnar cacti need to be grown in direct bright light. If grown indoors, place at a sunny south facing window. Pot in well-drained soil and allow to dry between watering.

LATIN LOOKUP – Loquerisne Latine (Do you speak Latin)?

The meanings of latin plant names on this page – from http://davesgarden.com/guides/botanary/

• Cephalocereus [sef-uh-low-KER-ee-us, sef-uh-low-SER-ee-us]
  From the Greek kephale (head) and Cereus (a genus of cactus), referring to the woolly head on mature specimens.
• cochal [KOH-kal]
  From the Baja California, Mexico local vernacular name for the Myrtillocactus species.
• Echinocactus [ek-in-oh-KAK-tus]
  From the Greek echinos (porcupine, hedgehog) and cactus, referring to its spines.
• eruca [er-ROO-kuh]
  Classical Latin name used by Pliny.
• Ferocactus [fer-oh-KAK-tus]
  From the Latin ferus, (fierce) and cactus, referring to its heavy spines.
• geometrizans [jee-oh-MET-rih-zans]
  Geometric; having markings in a formal pattern.
• marginatus [mar-jen-AY-tus, mar-jeh-NAH-tus]
  Margined.
• Myrtillocactus [mir-til-oh-KAK-tus]
  From the Greek myrtillus (small myrtle) and cactus; referring to the myrtle-like fruits.
• Pachycereus [pak-ee-KER-ee-us, pak-ee-SER-ee-us]
  From the Greek pachys (thick) and cereus (cactus).
• palmeri [PALM-er-ee]
  Named for Ernest Jesse Palmer, 20th century English-born American explorer and plant collector.
• Pilosocereus [pil-oh-so-KER-ee-us, pil-oh-so-SER-ee-us]
  Hairy wax taper, hairy Cereus.
• pilosus [pil-OH-sus]
  Covered in soft, long hair.
• platyacanthus [plat-ee-a-KAN-thus]
  From the Greek platys (broad) and akantha (thorn).
• pringlei [PRING-lee-eye]
  Named for Cyrus Guernsey Pringle, 19th century American botanist, collector and plant breeder.
• schottii [SHOT-ee-eye]
  Named for Arthur Carl Victor Schott, 19th century German-born naturalist on the Mexican boundary survey.
• senilis [SEE-nil-is]
  Of an old man.
• Stenocereus [sten-oh-KER-ee-us]
  From the Greek stenos (narrow) and cereus (genus name for cactus, meaning torch).
• thurberi [THUR-ber-eye]
  Named for Dr. George Thurber, 19th century botanist and quartermaster of the United States Mexican Boundary Commission.