Maihuenia

Morphological Summary

Maihuenia is a small genus of cacti in the subfamily Maihuenioideae, considered one of the most primitive within Cactaceae along with Pereskia. Its two species form creeping cushions or dense pads of short cylindrical stems bearing small persistent leaves (unlike most cacti), long spines, and solitary yellow flowers. They are endemic to the arid and semi-arid regions of the Andes and Patagonia of Chile and Argentina, where they endure extreme conditions: intense frosts to -20 °C, hurricane-force winds, winter snow, and poor volcanic rock or gravel soils. They are among the few Cactaceae tolerant of prolonged freezing temperatures. Phylogenetically, Maihuenia retains ancestral characters of Cactaceae: its persistent rudimentary leaves and flower and fruit structure reveal the evolutionary "missing link" between normal-leaved plants and leafless succulent cacti. The genus was described by F.A.C. Weber in 1898.