Austrocedrus Florin & Boutelje

Austrocedrus is one of several predominantly southern hemisphere members of the Cupressaceae that was segregated from a broad-concept Libocedrus during the 20th century (Farjon 2005). The sole species, A. chilensis, had been known to Europeans long before it was first described to science by David Don in 1832. Don initially treated it in Thuja, which it resembles but is not especially closely related to, before Stephan Endlicher transferred it to Libocedrus when he described that genus in 1847.

The publication of Austrocedrus in 1954 followed that of Pilgerodendron in 1930 (another Libocedrus segregate), and consequently the three South American cypresses (Austrocedrus chilensis, Pilgerodendron uvierfum and Fitzroya cupressoides) all attained equal status as endemic, monospecific genera.

The delimitation of genera in this region of Cupressaceae continues to be debated among conifer taxonomists, though more for sport than science. One of the most recent phylogenomic analyses of extant gymnosperms (Yang et al. 2022) places Austrocedrus sister to the monospecific subtropical Malesian genus Papuacedrus, those two in turn sister to another clade that contains Pilgerodendron and Libocedrus, and a third clade that contains, in an uncertain arrangement, Widdringtonia, Diselma, Fitzroya and Callitris. These results could be interpreted to support the sinking of Austrocedrus into Papuacedrus (which as the older name would be the valid one) and the return of Pilgerodendron to Libocedrus, but the mainstream view has for some time favoured the relatively narrow genus concept (supported by biogeography) that saw Libocedrus carved up in the first place, and a return to broader concepts seems unlikely.