Pterocacteae

What is Pterocacteae?

Pterocacteae Kuntze is a predominantly South American tribe within Opuntioideae. The broad 2025 phylogenomic classification of Cactaceae notes that the name Pterocacteae has nomenclatural priority over the later Tephrocacteae. In that treatment, lineages formerly placed under Austrocylindropuntieae or Tephrocacteae are brought together within a broader Pterocacteae.¹

Circumscription

The current circumscription includes five principal genera: Austrocylindropuntia, Cumulopuntia, Maihueniopsis, Pterocactus, and Tephrocactus.¹ Several smaller generic names are treated as synonyms or segregates within these lineages. The phylogenomic classification, for example, places Punotia very close to Austrocylindropuntia and treats Puna within Maihueniopsis.

Members are mainly terrestrial plants with segmented, cylindrical stems. Dwarf cushion-forming and geophytic forms with thickened underground organs are common, although Austrocylindropuntia also contains medium-sized shrubs and small tree-like plants. This breadth of form means that the tribe cannot be diagnosed by a single growth habit.

Phylogenetic relationships

The large nuclear dataset supports a close relationship between Cumulopuntia and Austrocylindropuntia. Punotia was also recovered as a strongly supported close relative of Austrocylindropuntia.¹ The order of the earliest branches within the tribe is less secure: some nodes involving Maihueniopsis and Pterocactus have low support or vary among analyses.

Pterocacteae is therefore used here as the current priority-correct tribal name without implying that every relationship inside the tribe is settled. Older literature may use “Tephrocacteae” for a similar or narrower concept, and those usages should be interpreted in their historical context.

References

1. 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 ↩