What are the criteria for determining the belonging of plants to the gymnosperms division?

Gymnosperms can be easily distinguished from angiosperms in two ways. Firstly, gymnosperms do not bloom, their pollen for fertilization is formed in male cones, from where it spreads with the help of the wind or, less often, insects. Secondly, in gymnosperms, the seeds are not covered by the fruit, but are either in female cones, like in conifers, or they can hang separately, like in ginkgo trees. In total, four genera of gymnosperms remained in nature: conifers, ginkgo, cycad and oppressive, although earlier they were very common.