Chestnut dioon Dioon edule, copyright Wayne.

Belongs within: Spermatophyta.
Contains: Cycas, Macrozamia, Encephalartos, Ceratozamia, Zamia.

The Cycadophyta, cycads, are a group of superficially palm-like gymnosperms. The name ‘Cycadophyta’ was defined by Cantino et al. (2007) to refer to the cycad crown group, characterised by the presence of cone domes, vascular strands crossing the pith within the stem. These result from the sympodial growth of the plant: each successive cone represents the termination of the apical meristem, and growth is continued through the production of a secondary subapical bud that eventually overtops the old cone and displaces it to one side.

Cycads may be divided between the Cycadaceae, in which leaflets have a single midrib, and Zamiaceae, in which leaflets have multiple veins. Bowenia is a genus of cycads found in northeastern Australia distinguished by its bipinnate leaves.

<==Cycadophyta [Cycadales, Cycadeae]
    |--Cycadaceae [Cycadineae]NM11
    |    |--ZamiphyllumP92
    |    `--CycasNM11
    `--Zamiaceae [Zamiineae]NM11
         |  `--+--EncephalartosNM11
         |     `--LepidozamiaNM11
         |          |--L. hopeiNM11
         |          `--L. peroffskyanaNM11
            |    |--D. spinulosumNM11
            |    `--+--D. eduleNM11
            |       `--+--D. tomaselliiNM11
            |          `--+--D. merolaeNM11
            |             `--D. purpusiiNM11
               |    |--B. serrulataNM11
               |    `--B. spectabilisPL12
               `--+--+--Stangeria eriopusNM11
                  |  `--CeratozamiaNM11
                  `--+--Microcycas calocomaNM11
Cycadophyta incertae sedis:
    |--T. daintreeiF71
    |--T. multinervisG31
    |--T. taiyuanensis Halle 1927C93
    |--T. triassica Walkom 1925F71
    `--T. vittataT30
    |--A. balmeiPL12
    |--A. szeiPL12
    `--A. wonnacottiPL12
  Delemaya spinulosaPL12
  Lesleya cheimarosa Leary & Pfefferkorn 1977C93
  Archaeocycas whitei Mamay 1973C93
  Phasmatocycas kansana Mamay 1973C93
  Sobernheimia jonkeri Kerp 1983C93
    |--C. chinensis (Zhu & Du) Gao & Thomas 1989C93
    |--C. cucullata (Halle) Gao & Thomas 1989C93
    |--C. minor Gao & Thomas 1989C93
    `--C. spadicia Gao & Thomas 1989C93
  Tianbaolinia circinalis Gao & Thomas 1989C93
  Yuania chinensis Zhu & Du 1981C93
  Lasiostrobus polysaccii Taylor 1969C93
    |--O. feistmanteliK-CB01
    |--O. mimetesK-CB01
    |--O. parallelusK-CB01
    |--O. ramonensisK-CB01
    |--O. simpsoniiK-CB01
    `--O. veronensisK-CB01

*Type species of generic name indicated


[C93] Cleal, C. J. 1993. Gymnospermophyta. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 795–808. Chapman & Hall: London.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.

[G31] Grabau, A. W. 1931. The Permian of Mongolia: A report on the Permian fauna of the Jisu Honguer limestone of Mongolia and its relations to the Permian of other parts of the world. American Museum of Natural History: New York.

[K-CB01] Konijnenburg-van Cittert, H. van, & K. Bandel. 2001. Jurassic plants from Djebel Tih, Sinai. Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg 85: 47–64.

[NM11] Nagalingum, N. S., C. R. Marshall, T. B. Quental, H. S. Rai, D. P. Little & S. Mathews. 2011. Recent synchronous radiation of a living fossil. Science 334: 796–799.

[PL12] Peñalver, E., C. C. Labandeira, E. Barrón, X. Delclòs, P. Nel, A. Nel, P. Tafforeau & C. Soriano. 2012. Thrips pollination of Mesozoic gymnosperms. Proceedings of the National Academy of Sciences of the USA 109 (22): 8623–8628.

[P92] Poinar, G. O., Jr. 1992. Life in Amber. Stanford University Press: Stanford.

[T30] Thomas, H. H. 1930. Further observations on the cuticle structure of Mesozoic cycadean fronds. Proceedings of the Linnean Society of London 141: 5–7.

[WL10] Wang, Y., Z. Liu, X. Wang, C. Shih, Y. Zhao, M. S. Engel & D. Ren. 2010. Ancient pinnate leaf mimesis among lacewings. Proceedings of the National Academy of Sciences of the USA 107 (37): 16212–16215.

[Z02] Zherikhin, V. V. 2002. Ecological history of the terrestrial insects. In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 331–388. Kluwer Academic Publishers: Dordrecht.

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