Classification of gymnosperms by gifford and foster?

Answer 1

In early classification schemes, the gymnosperms (Gymnospermae) were regarded as a "natural" group. There is conflicting evidence on the question of whether the living gymnosperms form aclade.[1][2]The fossil record of gymnosperms includes many distinctive taxa that do not belong to the four modern groups, including seed-bearing trees that have a somewhat fern-like vegetative morphology (the so-called seed ferns or pteridosperms.)[3]When fossil gymnosperms such asBennettitales, Caytonia and the glossopterids are considered, it is clear that angiosperms are nested within a larger gymnosperm clade, although which group of gymnosperms are their closest relatives remains unclear. For the most recent classification on extant gymnosperms see Christenhusz et al. (2011)[4]

Classification:'

SUBCLASS CYCADIDAE

• ORDER CYCADALES
  • Family Cycadaceae: Cycas
  • Family Zamiaceae: Dioon, Bowenia, Macrozamia, Lepidozamia, Encephalartos, Stangeria,Ceratozamia, Microcycas, Zamia.

SUBCLASS GINKGOIDAE

• ORDER GINKGOALES
  • Family Ginkgoaceae: Ginkgo

SUBCLASS GNETIDAE

• ORDER WELWITSCHIALES
  • Family Welwitschiaceae: Welwitschia
• ORDER GNETALES
  • Family 'Gnetaceae: Gnetum
• ORDER EPHEDRALES
  • Family Ephedraceae: Ephedra

SUBCLASS PINIDAE

• ORDER PINALES
  • Family Pinaceae: Cedrus, Pinus, Cathaya, Picea, Pseudotsuga, Larix, Pseudolarix,Tsuga, Nothotsuga, Keteleeria, Abies
• ORDER ARAUCARIALES
  • Family Araucariaceae: Araucaria, Wollemia, Agathis
  • Family Podocarpaceae: Phyllocladus, Lepidothamnus, Prumnopitys, Sundacarpus,Halocarpus, Parasitaxus, Lagarostrobos, Manoao, Saxegothaea, Microcachrys,Pherosphaera, Acmopyle, Dacrycarpus, Dacrydium, Falcatifolium, Retrophyllum, Nageia,Afrocarpus, Podocarpus
• ORDER CUPRESSALES
  • Family Sciadopityaceae: Sciadopitys
  • Family Cupressaceae: Cunninghamia, Taiwania, Athrotaxis, Metasequoia, Sequoia, Sequoiadendron, Cryptomeria, Glyptostrobus,Taxodium, Papuacedrus, Austrocedrus, Libocedrus, Pilgerodendron, Widdringtonia, Diselma, Fitzroya, Callitris, Actinostrobus,Neocallitropsis, Thujopsis, Thuja, Fokienia, Chamaecyparis, Cupressus, Juniperus, Calocedrus, Tetraclinis, Platycladus, Microbiota
  • Family Taxaceae: Austrotaxus, Pseudotaxus, Taxus, Cephalotaxus, Amentotaxus, Torreya

Answer 2

Gifford and Foster classified gymnosperms into four divisions: Cycadophyta (cycads), Ginkgophyta (ginkgo), Pinophyta (conifers), and Gnetophyta (gnetophytes). Each division is characterized by distinct features such as leaf structure, reproductive organs, and overall morphology. This classification system provides a framework for understanding the diversity and relationships among gymnosperms.