Emplectopteridaceae

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Emplectopteridaceae
Temporal range: Permian
Scientific classification e
Kingdom: Plantae
Division: Pteridospermatophyta
Order: Callistophytales
Family: Emplectopteridaceae

The Emplectopteridaceae were pteridosperms known mainly from Permian floras of the Cathaysian Realm. They were mostly shrubby plants with a scrambling or upright habit, and favoured a range of habitats from arid to moist or even aquatic.[1] The foliage is the most abundant known remains of this family, having been reported from Artinskian to Wuchiapingian macrofloras of both north and south China.[2] [3] [2] The venation is characteristically flexuous to loosely anastomosed, and rather different from the more regularly anastomosed venation of the true gigantopterids (with which the Emplctopteridaceae fronds used to be confused). The stratigraphically older leaves tended to be twice pinnate (Emplectopteris), the later leaves once pinnate or entire (Gigantonoclea).[4] The ovules were bilateral and attached to the underside of the leaves / fronds that did not differ significantly from normal vegetative foliage[5] Pollen organs were a complex of filiform microsporophylls each bearing 2-8 sporangia (assigned to the fossil-genus Jiaochengia).[1]

The family is currently only known from adpressions (compression-impressions) and the consequential lack of anatomical evidence has resulted in some disagreement as to its affinities. However, the form and position of attachment of the ovules strongly suggests affinities with the callistophytaleans.[1]

The family is only reliably reported from China. Gigantonoclea-like leaves have also been reported from Permian macrofloras of North America[6] but without any evidence of reproductive structures and the affiniity of these leaves may lie nearer to the Peltaspermales..[7]

References[edit]

  1. ^ a b c Wang Ziqiang. 1999. Gigantonoclea: an enigmatic Permian plant from north China. Palaeontology, 42, 329-373.
  2. ^ a b Shen Guanlong. 1995, Permian floras. In Li Xingxue, Zhou Zhiyan, Cai Chongyang, Sun Ge, Ouyang Shu & Deng Longhua (eds) Fossil floras of China through the geological ages. Guandong Science and Technology Press, Guandong, pp. 127-223.
  3. ^ Glasspool, I. J., Hilton, J., Collinson, M. E., Wang Shijun & Li Chengsen. 2004. Foliar physiognomy in Cathaysian gigantopterids and the potential to track Palaeozoic climates using an extinct plant group. Review of Palaeobotany and Palynology, 205, 69-110.
  4. ^ Asama, K. 1962. Evidence of Shanxi flora and origin of simple leaf. Science Reports, Tohoku University, 2nd Series (Geology), Special Volume, 5, 247-274.
  5. ^ Halle, T. G. (1932). "On the seeds of the pteridosperm Emplectopteris triangularis." Geological Society of China Bulletin, 11, 301-306.
  6. ^ Mamay, S. H. 1988. Gigantoclea in the lower Permian of Texas. Phytologia, 64, 330-332.
  7. ^ Anderson, J. M., Anderson, H. M. & Cleal, C. J. (2007). "Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology." Strelitzia, 20: 1-279.

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