Etude systématique du sous-genre Oxycedrus (section oxycedroides) du genre Juniperus (Cupressaceae)

Abstract

Some biochemical (foliar proanthocyanidins) and morphometric (seeds and galbulos) parameters of the taxa Juniperus oxycedrus L. sensu lato (Mediterranean area), Juniperus cedrus Webb. & Berth, (endemic of the Canary Islands and Madeira) and Juniperus brevifolia (Seub.) Antoine (endemic of the Azores Islands), section oxycedroides, subgenus Oxycedrus, genus Juniperus (Cupressaceae, Conifers), have been studied. Due to their low prodelphinidin content, Oxycedrus junipers from Turkey and Cyprus can be considered as the extreme representatives to the subspecies oxycedrus. Reversibly, the Cretan population studied, with high prodelphinidin content, appears to be the maximum homozygotic expression of the proanthocyanic biosynthesis (subspecies macrocarpa). Proanthocyanic content and the number of the seeds unquestionably link J. brevifolia to the J. oxycedrus complex ; however, we propose to maintain this taxon as a species in view of the small size of its needles. J. cedrus generally contains one seed only by galbulus ; moreover, there is a contradiction between the absolute proanthocyanic content (low) and the relative prodelphinidin content (fairly high). This confers it an unquestionable specific originality. In the end, we propose to consider all the representatives of the Mediterraneo-atlantic group of the oxycedroides section (J. oxycedrus, J. macrocarpa, J. cedrus, J. brevifolia) as diversely related taxa within a Juniperus aggr. oxycedrus complex, with a good chemical and morphogenetical consistency. A parallel has been established with J. aggr. communis, an other representative of the same sub-genus Oxycedrus.