Subfamily

Opuntioideae

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The diagnostic features of Opuntioideae, its current three-tribe classification, and the placement of Pterocacteae.

Position of Opuntioideae within Cactaceae

Opuntioideae is a well-supported lineage of the cactus family. The current phylogenomic classification treats it as a monophyletic group and organizes its diversity into three tribes: Opuntieae, Cylindropuntieae, and Pterocacteae.¹ This framework combines morphological evidence with phylogenetic signal from hundreds of nuclear genes rather than relying on outward similarity alone.

Diagnostic structure

Members range from dwarf shrubs to tree-like cacti. Their stems are commonly jointed and segmented, with segments that may be cylindrical or flattened into cladodes. Spine-bearing areoles are interpreted as condensed short-shoot systems in the axils of primary leaves. One of the most recognizable features of the subfamily is the presence of glochids, minute and readily detachable barbed structures.¹

Leaves are reduced to short-lived rudiments on new growth in many members, but the subfamily is not uniform in this respect. Species such as Austrocylindropuntia subulata retain conspicuous, fleshy, persistent true leaves. Opuntioideae therefore cannot be described accurately by a simple “leafless cactus” formula.

The current three-tribe framework

Opuntieae contains mostly American lineages with flattened cladodes or varied stem architectures. Cylindropuntieae, in its narrower modern circumscription, is largely a North American lineage with cylindrical segments. Pterocacteae brings together principally South American lineages including Austrocylindropuntia, Cumulopuntia, Maihueniopsis, Pterocactus, and Tephrocactus.¹

Each tribe is supported, but their exact branching order is not identical across analyses. The phylogenomic study reports conflicting gene-tree signals over whether Pterocacteae is closer to Cylindropuntieae or Opuntieae. The hierarchy shown here follows the current classification without presenting uncertain internal nodes as a settled evolutionary sequence.

References

de Vos, J.M. et al. “Phylogenomics and classification of Cactaceae based on hundreds of nuclear genes.” Plant Systematics and Evolution 311, 28. Accessed: 2026-08-03. https://doi.org/10.1007/s00606-025-01948-z ↩

Child Taxa

TribeTephrocactus TribeTephrocacteae TribePterocacteaePterocacteae

Plants In This Group

Austrocylindropuntia cylindrica

Austrocylindropuntia cylindrica is a cylindrical segmented cactus associated with the Andean region of Central Colombia, Ecuador, and north western Peru. It may develop as a shrub or small tree. The ageing main stem can become woody, while dark or bluish green shoots carry conspicuous rhomboid tubercles.

Austrocylindropuntia floccosa

Austrocylindropuntia floccosa is a remarkable cushion forming succulent shrub adapted to the harsh conditions of the high altitude Andean plateaus. It is famous for its dense covering of white, wool like hairs that shield the plant from freezing temperatures and intense solar radiation.

Austrocylindropuntia lagopus

Austrocylindropuntia lagopus is a fascinating high altitude cactus species native to the Andean highlands. Characterized by its dense cushion forming growth habit and a thick blanket of soft, white woolly hairs, this plant is evolutionary designed to withstand extreme cold and intense solar radiation . It is highly sought after by succulent collectors for its unique, cloud like appearance.

Austrocylindropuntia lauliacoana

Austrocylindropuntia lauliacoana is a succulent subshrub in the family Cactaceae, native to the high altitude Andean regions of Peru. Adapted to harsh mountain environments, this species is highly valued by specialized collectors for its unique cylindrical form and defensive spination .

Austrocylindropuntia pachypus

Austrocylindropuntia pachypus is a distinctive and highly sought after columnar cactus species within the Cactaceae family. Developing a shrubby or subshrubby habit in its natural environment, this succulent is greatly valued by collectors for its unique spiraling tubercles and dense spine coverage .

Austrocylindropuntia shaferi

Austrocylindropuntia shaferi is a distinct, shrubby succulent cactus belonging to the family Cactaceae . Characterized by its upright cylindrical stems and prominent spination, this species is highly adapted to arid and semi arid montane environments.

Austrocylindropuntia subulata

Austrocylindropuntia subulata is a cactus native to the dry Andean region of Peru and Bolivia. With age it can become a shrub or small tree like plant. Its upright main stem may become woody, while the green lateral shoots are cylindrical and distinctly tuberculate. Areoles on the tubercles can carry strong spines and minute, irritating glochids.

Austrocylindropuntia vestita

Native to the arid landscapes of the high Andes Mountains in South America, Austrocylindropuntia vestita is a fascinating member of the cactus family (Cactaceae). Also known as "Woolly Opuntia" or "Old Man Opuntia," this plant stands out due to its distinctive appearance. Its stems are typically cylindrical and densely covered with white hairs and spines, giving it a "woolly" or "old man" look. These hairs serve as a natural adaptation mechanism, protecting the plant from both excessive sunlight and freezing temperatures .

Tephrocactus geometricus

Golf Ball Cactus

Tephrocactus geometricus is a succulent subshrub in family Cactaceae, native to Catamarca in Argentina. The current Kew backbone treats it as an independently accepted species, and the 2019 Tephrocactus phylogeny supports that distinction using molecular and morphological evidence.