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Containing group: Spermatopsida

References

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Carlquist, S. 1996. Wood, bark, and stem anatomy of Gnetales: A summary. International Journal of Plant Sciences157(6, Suppl.): S58-S76.

Crane, P. R. 1996. The fossil history of the Gnetales. International Journal of Plant Sciences157(6, Suppl.): S50-S57.

Crane, P. R., and S. Lidgard. 1989. Angiosperm diversification and paleolatitudinal gradients in Cretaceous floristic diversity. Science 246:675-678.

Crane, P. R., and G. R. Upchurch Jr. 1987. Drewria potomacensis gen. et sp. nov., an Early Cretaceous member of Gnetales from the Potomac Group of Virginia. Am. J. Bot. 74:1722-1736.

Dilcher, D. L., M. E. Bernardes-De-Oliveira, D. Pons, and T. A. Lott. 2005. Welwitschiaceae from the Lower Cretaceous of northeastern Brazil. American Journal of Botany 92:1294-1310.

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Donoghue, M.J. and S.M. Scheiner. 1992. The evolution of endosperm: a phylogenetic account. In Ecology and Evolution of Plant Reproduction: New Approaches, pp.356-389; R. Wyatt (ed.). New York: Chapman and Hall.

Doyle, J. A. 1996. Seed plant phylogeny and the relationships of Gnetales. International Journal of Plant Sciences157(6, Suppl.): S3-S39.

Doyle, J. A., and M. J. Donoghue. 1986. Seed plant phylogeny and the origin of angiosperms: An experimental cladistic approach. Bot. Rev. 52:321-431.

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Endress, P. K. 1996. Structure and function of female and bisexual organ complexes in Gnetales. International Journal of Plant Sciences157(6, Suppl.): S113-S125.

Friedman, W. E. 1990. Double fertilization in Ephedra, a nonflowering seed plant: Its bearing on the origin of angiosperms. Science 247:951-954.

Friedman, W. E. 1992. Evidence of a pre-angiosperm origin of endosperm: Implications for the evolution of flowering plants. Science 225:336-339.

Friedman, W. E. 1994. The evolution of embryogeny in seed plants and the developmenal origin and early history of endosperm. Am. J. Bot. 81:109:153-226.

Friedman, W. E. 1996. Introduction to biology and evolution of the Gnetales. International Journal of Plant Sciences157(6, Suppl.): S1-S2.

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Jacobson K. M., and E. Lester. 2003. A first assessment of genetic variation in Welwitschia mirabilis Hook. Journal of Heredity 94:212-217.

Martens, P. 1971. Les Gnetophytes (Handbuch der Pflanzenanatomie, Band 12, Teil 2). Gebrueder Borntraeger, Berlin.

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Rydin C., B. Mohr, and E. M. Friis 2003. Cratonia cotyledon gen. et sp. nov.: a unique Cretaceous seedling related to Welwitschia. Proceedings of the Royal Society of London B, Biology Letters (Supplement) 270:1?4.