Morphology of Equisetum laterale Phillips, 1829, and E. bryanii sp. nov. from the Mesozoic of South-Eastern Queensland

Abstract

An equisetaceous plant with wheel-like nodal diaphragms, previously described as Equisetum rotiferum Tenison-Woods, 1883, is common in the Marburg Sandstone and Walloon Coal Measures of south-eastern Queensland. The species is now considered to be synonymous with E. laterale Phillips, 1829.E. bryanii sp. nov. occurs in the Walloon and Mulgildie Coal Measures. Both forms are described in detail and can be closely compared with extant Equisetum. The internodal vascular bundles of E. laterale contain xylem elements with annular, annular-helical, and reticulate thickenings, annular types predominating. The cone of E. laterale is ovate and terminal, consisting of whorled peltate sporangiophores; it contains numerous small, globose, alete, scabrate to microrugulate spores.