Opuntia alta, Tree Pricklypear

Opuntia alta
Opuntia alta

Griffiths, Annual Report of the Missouri Botanical Garden 21: 165, 1910 

Holotype; Holotype; Isotype; Herbarium; Painting (Annals of the Missouri Botanical Garden 21: 165, 1910, Plate 19)

O. cacanapa is another arborescent Opuntia

Original citation

What is Opuntia alta?

Opuntia  alta is a large, arborescent species of prickly pear cactus. Mature individuals may reach heights of 3 to 4 meters, forming tree-like structures with a prominent central trunk. In older specimens, the main trunk may attain diameters of up to 0.5 meters. The species typically exhibits a single, dominant trunk supporting an elevated canopy of cladodes, giving the plant a distinctly tree-like appearance uncommon in most Opuntia species.

Details

The cladodes of Opuntia alta are generally uniform in shape, varying from subcircular to ovate or obovate, but rarely elongate. Spines are yellow, measuring 1 to 1.5 cm in length, and are often fewer in number compared to those of O. lindheimeri. Glochids may be distributed across the entire areole, similar to O. lindheimeri and O. engelmannii. Areoles may become slightly raised with age.

Flowers are predominantly lemon-yellow and smaller than those of O. lindheimeri or O. engelmannii. Occasionally, flowers appear greenish-yellow or pale-yellow, while reddish flowers are rare. Fruits are roundish to ovoid, relatively small, often numerous, and typically lack a pronounced neck, although they may taper slightly toward the base. Notably, despite the large overall size of the plant, its fruits are smaller than those of O. lindheimeri.

O. alta has been reported to be diploid or hexaploid by different sources. 

Other Notes

Britton and Rose (1919) reported O. alta as one of the tallest—if not the tallest—Opuntia species in the United States. Mature plants form large, distinct trunks even when sprawling rather than upright and generally attain a much greater size than O. lindheimeri. A distinguishing floral trait includes the stigma coloration; O. alta may exhibit yellow to pale-green stigmas, whereas O. lindheimeri has distinctly green stigmas.

A specimen propagated from material collected near Laredo, Texas, was cultivated outdoors under protection at the Rio Grande Botanic Garden in Albuquerque, New Mexico, surviving for over six years despite annual winter damage. This indicates that with adequate protection, O. alta can tolerate substantial cold.

Due to its large size, O. alta may be unsuitable for many garden settings. However, smaller plants can be maintained for extended periods with proper pruning. The species produces abundant flowers and fruits, though its flowers are relatively small.

For more information, see:

Garcia-Morales, L.G., Garcia-Jimenez J., Contreras-Medina R., Alcántara-Ayala O., and Luna-Vega I. (2022) Diversity, distribution, and conservation of the Cactaceae (Caryophyllales) from Tamaulipas, Mexico, Biodiversity and Conservation. 156:1405.

Shaw, J. Opuntia alta Griffiths, Description and Synonyms (Cactaceae, Opuntioideae) . 

 

1 thought on “Opuntia alta, Tree Pricklypear”

  1. Barry

    I have a plant that is either Opuntia cacanapa or Opuntia alta how am I able to tell the difference between the two mine has up to 3 yellow spines in a glochid but that’s rare most have 1 some have none but still have glochids they both have curling leaves so do mine they both form a trunk mine is doing so and he’s grown 13 pads this year alone so far

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