An Upper Pliocene Equisetum (Equisetales) from the Atotonilco El Grande Formation in Central Mexico

Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic

“…The Mesozoic sphenophyte fossils were assigned to the organ genus Equisetostachys and the fossil genus Equisetites , sharing some morphological similarities with extant Equisetum ( Kelber and van Konijnenburg-van Cittert, 1998 ; DiMichele et al., 2005 ; Villar de Seoane, 2005 ; Weber 2005 ). However, most Cenozoic sphenophyte fossils, especially the vegetative parts, have been assigned to the genus Equisetum ( Table 1 ; Si and Li, 1963 ; Mei and Tian, 1988 ; Taylor and Taylor, 1993 ; Kelber and van Konijnenburg-van Cittert, 1998 ; Silva–Pineda et al., 2009 ).…”

“… America Stem Knowlton (1902) E. aravense United States – Knowlton et al (1921) E . myriochaetum Central Mexico Fragmented stem Silva–Pineda et al. (2009) Equisetum sp.…”

“…, E. arcticum Pavlyutkin et al.) from the Cenozoic Period of Asia, North America, Europe, and Africa ( Table 2 ; Knowlton, 1902 ; Jennings 1920 ; Smith, 1938 ; Bell, 1949 ; Graham, 1963 ; Becker, 1973 ; Brown, 1975 ; Hickey, 1977 ; Mciver and Basinger, 1989 ; Verdcour, 1999 ; Uhl et al., 2002 ; Silva–Pineda et al., 2009 ; Pole and McLoughlin, 2017 ; Chen et al, 2021 ; Pavlyutkin et al., 2020 ). The current Siwalik specimens are characterized by the narrow-jointed stem, 10–15 mm long internodes, 10–12 teeth present in deep brown leaf sheath, basal fused lamina, and apically pointed tip with longitudinal striae, key characters that differentiate our specimens from earlier reported stem fossil species of Equisetum .…”

“… 5 mm – 16 8 mm 16 Sharp teeth – – – Knowlton (1902) E . myriochaetum 4–20 mm 13–82 mm 4–20 – – Sharp teeth 3–5 mm 0.5 mm – Silva–Pineda et al. (2009) E .…”

Antioxidant and Antiproliferative Activity of the Ethanolic Extract of Equisetum myriochaetum and Molecular Docking of Its Main Metabolites (Apigenin, Kaempferol, and Quercetin) on β-Tubulin

“…The genus Equisetum (Equisetaceae) includes 15 species of perennial herbs with a nearly cosmopolitan distribution, which mostly inhabit aquatic environments or swamps [ 1 , 2 ]. The species E. hyemale (L.) and E. myriochaetum (Schltdl.…”