Ginkgoopsida is a proposedclass ofgymnosperms defined by Sergei V. Meyen in 1984 to encompassGinkgoales (which contains the livingGinkgo) alongside a number of extinct seed plant groups, which he considered to be closely related based on similarities of morphology of pollen, seeds, cuticles, short shoots and leaves.[1][2][3] The validity of this group as a whole has been considered questionable by other authors, who consider that it is unlikely to bemonophyletic.[4] Other authors have used the class as a monotypic grouping, including only Ginkgoales.[5] Some authors have used the cladeGinkgophyta to encompass both Ginkgoales andCzekanowskiales/Leptostrobales, which are suggested to be closely related groups.[6]
