Aextoxicon is the sole genus in the monotypic family Aextoxicaceae (order Berberidopsidales), native to the temperate rainforests of southern Chile and adjacent Argentina. It contains a single species, Aextoxicon punctatum (Ruiz et Pav.), known commonly as olivillo, tique, or palo muerto. Formerly placed in Euphorbiaceae, molecular systematics now places it in its own family within Berberidopsidales, a small order of core eudicots.
This is a large, dioecious evergreen tree reaching 15–20 m or more in height, with smooth, light-toned bark and a dense crown of dark green foliage. The leaves are opposite, oval to elongated, dark green above and paler beneath, with the underside conspicuously dotted with rusty peltate scales (trichomes). Young buds, shoots, and emerging leaves are densely coated in these scales, lending them a scorched or dead appearance — the origin of the common name "palo muerto" (dead tree). The flowers are small, actinomorphic, and unisexual, borne in pendent racemes. Each flower has five sepals and five white, star-shaped petals; male flowers bear five stamens opposite the sepals, while female flowers have two fused carpels forming a bilocular ovary. Pollination is presumably by wind or insects. The fruit is a single-seeded drupe that ripens to a dark violet color and closely resembles a small olive, hence the common name "olivillo."
Aextoxicon punctatum is a canopy or emergent tree in the Valdivian temperate rainforest and Magellanic subpolar forests. In the northernmost part of its range (Coquimbo and Valparaíso Regions), it survives only in relict coastal enclaves on fog-fed high slopes or in sheltered humid ravines. From the Maule and Bío Bío Regions south to Los Lagos, it becomes more continuous across both the coastal and Andean cordilleras, forming nearly pure stands in the Cordillera de la Costa and mixed evergreen forests in the central valley. In Argentina, it occurs along the middle Río Negro valley — where it is considered invasive on Choele Choel island — and in Lago Puelo National Park in Chubut. The species provides high-quality timber and plays a foundational role in the structure of southern Chile's temperate rainforest ecosystems.
Etymology
The genus name Aextoxicon is of uncertain origin. The common name "olivillo" (and "aceitunillo") derives from the fruit, a single-seeded drupe that closely resembles a small olive (oliva / aceituna). The name "palo muerto" (dead tree) refers to the dense covering of rusty peltate scales on new shoots and buds, which gives the foliage a scorched or dead appearance. Other Chilean common names include tique and teque.
Distribution
Aextoxicon punctatum is endemic to southern South America. In Chile, it ranges from Parque Nacional Fray Jorge (Coquimbo Region, ~30°S) south to the Chiloé Archipelago and Los Lagos Region (~43°S). In the northern portion of its range it is restricted to relict coastal sites dependent on fog moisture (camanchaca) or to humid ravines. From the Maule and Bío Bío Regions southward it becomes abundant and continuous across both the coastal and Andean cordilleras, forming nearly pure stands in the Cordillera de la Costa. In Argentina, it is present in the middle Río Negro valley (invasive on Choele Choel island) and in Lago Puelo National Park, Chubut Province. GBIF lists the genus with a single accepted descendant.
Ecology
Aextoxicon punctatum is a canopy or emergent tree of the Valdivian temperate rainforest and Magellanic subpolar forest ecoregions, typically in damp, humid sites. In its northernmost range limit (Coquimbo), populations are relictual and depend entirely on coastal fog (camanchaca) captured by high-elevation slopes. Further south, the species becomes a dominant forest component, capable of forming nearly pure stands in the coastal range and mixing with other evergreen species in the central valley and lower Andean slopes. The species is dioecious (separate male and female trees), with unisexual flowers borne in pendent racemes.
Taxonomy
Aextoxicon is the sole genus in the monotypic family Aextoxicaceae. Under the APG (1998) and APG II (2003) classifications, the family was left unplaced within the core eudicots. It has since been placed in the order Berberidopsidales. Historically, the genus was often included in Euphorbiaceae. The single species, Aextoxicon punctatum, was originally described by Ruiz and Pavón. GBIF records one accepted descendant taxon.
Uses
The wood of Aextoxicon punctatum is valued as a high-quality timber in its native range.
