Emplectopteridaceae Knowpia

Emplectopteridaceae; Temporal range: Artinskian–Wuchiapingian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	†Pteridospermatophyta
Class:	†Lyginopteridopsida (?)
Order:	†Callistophytales
Family:	†Emplectopteridaceae; Wagner, 1967

Emplectopteridaceae is an extinct family of pteridosperms ("seed ferns") known mainly from Permian floras of the Cathaysian Realm (corresponding to modern East Asia). 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] Their 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 bilaterally symmetrical 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 paucity 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] Emplectopterids have only reliably been 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 affinity of these leaves may lie nearer to the Peltaspermales.^[7]

List of genera edit

Emplectopteris leaves
Gigantonoclea leaves
Cornucarpus ovulate organ
Jiaochengia pollen organ

References edit

^ ^a ^b ^c Zi‐Qiang, Wang (1999). "GIgantonoclea : an enigmatic Permian plant from North China". Palaeontology. 42 (2): 329–373. doi:10.1111/1475-4983.00076. ISSN 0031-0239.
^ 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.
^ 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.
^ Asama, K. 1962. Evidence of Shanxi flora and origin of simple leaf. Science Reports, Tohoku University, 2nd Series (Geology), Special Volume, 5, 247-274.
^ Halle, T. G. (1932). "On the seeds of the pteridosperm Emplectopteris triangularis." Geological Society of China Bulletin, 11, 301-306.
^ Mamay, S. H. 1988. Gigantoclea in the lower Permian of Texas. Phytologia, 64, 330-332.
^ Anderson, J. M., Anderson, H. M. & Cleal, C. J. (2007). "Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology." Strelitzia, 20: 1-279.