Austrocedrus is a monotypic genus of conifers in the cypress family (Cupressaceae), containing a single species, Austrocedrus chilensis, commonly known as the cordilleran cypress, ciprés de la cordillera, or Chilean cedar. It belongs to the subfamily Callitroideae, a group of Southern Hemisphere genera associated with the ancient Antarctic flora, and is classified in the order Cupressales.
The cordilleran cypress is a slow-growing, narrowly conical evergreen tree reaching 10 to 24 metres in height. Its foliage consists of scale-like leaves arranged in decussate (opposite, alternating) pairs of unequal size: the larger pair measures 4–8 mm and the smaller pair 2–3 mm, together forming a flattened shoot. Each leaf bears a distinctive white stomatal stripe along its outer edge. The species is dioecious, meaning male and female cones are borne on separate plants. Seed cones are small (5–10 mm), bearing four scales — two sterile basal scales and two fertile scales, each carrying a pair of winged seeds 3–4 mm long.
Austrocedrus chilensis is native to the Valdivian temperate rain forests and the adjacent drier steppe-forests of central-southern Chile and western Argentina, spanning latitudes from roughly 33°S to 44°S. Within this range it occupies the evergreen mountain forests of the Andes, typically on drier sites near the temperate rainforest margin. It is often locally dominant on the eastern slopes of the Andes in southwestern Argentina, and also grows in mixed forests alongside Araucaria araucana and Nothofagus species. The genus has been introduced to botanical gardens in northwest Europe and the Pacific Northwest of North America.
Austrocedrus is closely related to the New Zealand and New Caledonian genus Libocedrus, and some botanists have treated it within that genus as Libocedrus chilensis. The generic name means "southern cedar," reflecting both its austral distribution and its cedar-like appearance.
Etymology
The generic name Austrocedrus is derived from the Latin austr- ("southern") and cedrus ("cedar"), meaning "southern cedar." This reflects both the tree's South American distribution and its superficial resemblance to true cedars.
Distribution
Austrocedrus chilensis is native to the Valdivian temperate rain forests and adjacent drier steppe-forests of central-southern Chile and western Argentina, from approximately 33°S to 44°S latitude. It grows on the eastern slopes of the Andes, frequently in association with Araucaria araucana and Nothofagus species, and has been introduced to botanical gardens in northwest Europe and the Pacific Northwest of North America.
Ecology
The cordilleran cypress grows in evergreen mountain forests of the Andes on drier sites near the temperate rainforest, where it is often locally dominant on eastern Andean slopes in southwestern Argentina. Young plants establish best under conditions of at least 8% soil humidity and intermediate to high solar radiation, reflecting a preference for well-lit, moderately moist montane habitats.
Taxonomy Notes
Austrocedrus belongs to the subfamily Callitroideae within Cupressaceae — a group of distinctly Southern Hemisphere genera thought to have origins in the ancient Antarctic flora. The genus is most closely related to Libocedrus of New Zealand and New Caledonia, and some taxonomists have subsumed it within Libocedrus as L. chilensis. Despite this affinity, Austrocedrus is considered less morphologically similar to Libocedrus than the other South American cypress genus Pilgerodendron is.
