Equisetum x schaffneri Milde

  • Authority

    Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

  • Family

    Equisetaceae

  • Scientific Name

    Equisetum x schaffneri Milde

  • Description

    Species Description - Stems with regular whorls of branches, to 7 m tall (to 4 m in Oaxaca), 3-22 mm diam., with 12-48 ridges; sheath green to brown at base; stomata in bands of 1-2(-3) in the grooves; branches with 6-8 ridges, with saw teeth or irregular tubercles; strobili terminal on branches and main stem, acute or with slight apiculum; spores abortive.

  • Discussion

    Type. Mexico. Veracruz: Orizaba, Schaffner 315 (B?). For synonyms, see Hauke (1963). Equisetum x schaffneri is a hybrid between E. myriochaetum and E. giganteum, although Equisetum giganteum is not known to occur in Mexico. Hauke (1963) suggested that E. x schaffneri is dispersed by an occasional good spore. Equisetum x schaffneri can be distinguished by its abortive spores and intermediacy in number of rows of stomata (E. giganteum with broad band, 3-4 rows). Equisetum giganteum is large with whorled branches, but the grooves have stomata in bands of two or more lines and branch ridges with flattened tubercles (as opposed to stomata in single lines and branch ridges with saw teeth in E. myriochaetum).

  • Distribution

    Wet to swampy soil, usually exposed; Cuicatlán, Teotitlán; 500-950 m. Mexico (Tam, Ver, Pue, Oax, Chis); Guat to Pan; Ven, Col to Peru. Oaxaca collections: 6661; Conzatti & González 661 (GH, US).

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