Porlieria is a small genus of flowering shrubs and small trees in the caltrop family, Zygophyllaceae, placed in the order Zygophyllales. The genus is native to dry subtropical regions of South America, with species occurring primarily in arid and semi-arid habitats across Chile, Peru, and adjacent areas.
Plants in the genus are characterised by their compact, woody habit and tolerance of xeric conditions. The leaves are typically small and pinnate — an adaptation common across drought-tolerant members of Zygophyllaceae. The flowers are small and typically yellow or violet, characteristic of the broader family.
The best-known species is Porlieria chilensis (Chilean guayacán or palo santo), endemic to Chile, where it grows in the coastal ranges and Andean foothills. Porlieria hygrometra, found in Peru and Bolivia, takes its species epithet from its hygroscopic response: leaflets fold inward in dry air and open with moisture. Porlieria angustifolia, a Texas–Mexico shrub formerly placed in this genus, has been reclassified as Guaiacum angustifolium.
The genus was named in honour of Don Antonio Porlier de Baxamar, a Spanish ambassador, reflecting the botanical tradition of commemorating patrons and diplomats in plant nomenclature.
Etymology
The name Porlieria honours Don Antonio Porlier de Baxamar, a Spanish ambassador, following the longstanding botanical convention of commemorating distinguished patrons in genus names.
Distribution
The genus is native to dry subtropical South America, with species recorded from Chile (where P. chilensis is endemic), Peru, and Bolivia. Habitats are arid to semi-arid, consistent with the xeric ecology of the Zygophyllaceae family.
Ecology
Species of Porlieria are adapted to hot, dry subtropical climates. Porlieria hygrometra displays a notable hygroscopic response — its leaflets fold closed during dry conditions and reopen in humid air, a trait reflected in its species name. The genus occupies coastal ranges, Andean foothills, and inter-Andean valleys at low to mid elevations.
Taxonomy Notes
Porlieria belongs to Zygophyllaceae (order Zygophyllales). GBIF recognises 2 accepted species. Porlieria angustifolia, long included in the genus, is now treated as Guaiacum angustifolium Engelm., removing a North American element and restricting the genus to South America.
