First insight into Araucaria araucana (Molina) K. Koch under its southernmost European growing condition: a proposed descriptor list for morphological characterization

Araucaria araucana is a south American endemic Conifer of conservation concern. After its introduction to Europe, this species has been often planted for ornamental purposes in parks and gardens, where its unusual appearance was admired. After the mid-1970s this tree received increasing attention from the nursery growers of Pistoia (Tuscany) and became of considerable economic importance. However, being one of the iconic threatened trees listed in CITES Appendix I, the international trade of these species is rigorously regulated. This study was aimed at developing a first morphological descriptor list for further phenotyping of in loco produced plant material. A first step of the research focused on the description and a better understanding of A. araucana phenological phases inferred from Mediterranean climate conditions. The second phase regarded the analysis of observed or measured morphological characteristics of the tree, branches, scales, inflorescences, fruits and seeds observed on a subset of 4 selected putative populations over a 3-year period of vegetative growth. The results allowed to select 39 most discriminant descriptors, which are presented together with their range of variability and classes. The achieved descriptor list represents a suitable tool for the selection of genotypes and for the breeding of A. araucana