Sphenopsida


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Sphenopsida

a subdivision of the Tracheophyta, including the horsetails(Equisetum).
References in periodicals archive ?
The ontogeny of Carboniferous arborescent Sphenopsida. Palaeontographica, ser.
The higher land plants evolved from the telome trusses of the primitive forms along three parallel lines, as indicated in the following table: Primitive Land Plants Lycopsida Sphenopsida Pteropsida Examples Selaginella Equisetum Phanerogams Lycopodium Ferns Lepidophyta Transitional Protolepido- Hyeniales Protopteridales Groups dendrales
The sporophyll of the Sphenopsida is believed to have arisen by a downward bending of the sporangium toward a common axis (recurvation, leading to anatropy, Fig.