Threatened species of Gymnospermae

The gymnosperms have been subdivided along a variety of different lines and the recent flood of information on fundamental taxonomic characters (such as chloroplast DNA) has led to further revisions. The principal point of contention between various schemes for dividing gymnosperms above the family level seems to be at what point in the hierarchy are distinctions to be made. Different taxonomic systems treat the gymnosperms as a single phylum with four subphyla or four orders.