Eoginkgoites

Eoginkgoites; Temporal range:
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Gymnosperms
Order:	†Bennettitales
Family:	†Williamsoniaceae
Genus:	†Eoginkgoites; Bock 1952
Type species
	Eoginkgoites sectoralis; Bock 1952[1]
Species
	E. davidsonii; E. gigantea; E. sectoralis; E. sydneyi;

Eoginkgoites is an extinct form genus of bennettitalean leaves from the Late Triassic of North America.[1][2] Despite its palmate (hand-shaped) appearance similar to some early ginkgo species, it belongs to a different gymnosperm order, the Bennettitales. The leaf is deeply segmented into five to seven narrow, club-shaped lobes (pinnae or leaflets) which twist around a very short rhachis. This leads to an overall fan-shaped leaf (similar to a ginkgo but much more strongly segmented) situated at the end of a long petiole (leaf stalk). The leaf has paracytic stomata (with subsidiary cells laterally flanking the guard cells) and veins which strongly branch and lead to a marginal vein at the edge of each leaflet. These structural traits are all shared with benettitaleans.[1][2] Williamsonia carolinensis, an ovule-bearing bennettitalean cone, has been found closely associated with Eoginkgoites leaves, seemingly confirming its benettitalean identity.[3]

References

Ash, Sidney R. (1976). "The Systematic Position of Eoginkgoites". American Journal of Botany. 63 (10): 1327–1331. doi:10.1002/j.1537-2197.1976.tb13218.x. ISSN 0002-9122.
Axsmith, Brian J.; Taylor, Thomas N.; Delevoryas, Theodore; Hope, Robert C. (1995). "A new species of Eoginkgoites from the Upper Triassic of North Carolina, USA". Review of Palaeobotany and Palynology. 85 (3–4): 189–198. doi:10.1016/0034-6667(94)00131-3.
Pott, Christian; Axsmith, Brian J. (2015). "Williamsonia carolinensis sp. nov. and Associated Eoginkgoites Foliage from the Upper Triassic Pekin Formation, North Carolina: Implications for Early Evolution in the Williamsoniaceae (Bennettitales)". International Journal of Plant Sciences. 176 (2): 174–185. doi:10.1086/679471. ISSN 1058-5893. S2CID 44559347.

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[:0-1] Ash, Sidney R. (1976). "The Systematic Position of Eoginkgoites". American Journal of Botany. 63 (10): 1327–1331. doi:10.1002/j.1537-2197.1976.tb13218.x. ISSN 0002-9122.

[:1-2] Axsmith, Brian J.; Taylor, Thomas N.; Delevoryas, Theodore; Hope, Robert C. (1995). "A new species of Eoginkgoites from the Upper Triassic of North Carolina, USA". Review of Palaeobotany and Palynology. 85 (3–4): 189–198. doi:10.1016/0034-6667(94)00131-3.

[3] Pott, Christian; Axsmith, Brian J. (2015). "Williamsonia carolinensis sp. nov. and Associated Eoginkgoites Foliage from the Upper Triassic Pekin Formation, North Carolina: Implications for Early Evolution in the Williamsoniaceae (Bennettitales)". International Journal of Plant Sciences. 176 (2): 174–185. doi:10.1086/679471. ISSN 1058-5893. S2CID 44559347.