Equisetum laevigatum A.Braun
Descripción
Stems 20–150 cm tall, 3–7 mm diam., unbranched except on damaged plants, yellowish green; sheaths with length:width ratio of 2:1 with black rim at distal edge, otherwise green; stomata in single lines, one line on each side of a groove; ridges 10–32, flattened to convex, smooth to tuberculate; sheaths green, elongate, 7–15 X 3–9 mm; teeth 10–32, each without articulation line but articulate and shedding early, leaving a dark rim on each sheath; stem cross sections with prominent vallecular collenchyma extending to the vallecular canal; carinal collenchyma of lesser extent; endodermis of the double common type; strobili terminal on stems, ca. 10–20 mm long, apices rounded or each with a small apiculum; 2n=216 (USA).A
Forma de vida
TerrestreA
Ejemplar revisado
BCN (Chambers 524, UC; Thorne 32038, UC; Wiggins & Demaree 4860, NY, 4871, UC, US). BCS (Thomas 7897, US). Dgo (Benítez Paredes 887, MEXU). Son (Wolf 2510, CAS).
Unverified, Doubtful, or Mistaken Reports. NL (Aguirre C. 639, UNL, cited by Aguirre Claverán, 1983, but this is E. hyemale).
A
Unverified, Doubtful, or Mistaken Reports. NL (Aguirre C. 639, UNL, cited by Aguirre Claverán, 1983, but this is E. hyemale).
A
Elevación
1130 – 1850 mA
Tipo de vegetación
Bosque de pino-encinoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Equisetum laevigatum is limited in Mexico to the northwestern states and is distinct by the stem ridges lacking prominent tubercles, cones rounded apically, teeth without conspicuous articulation, and prominent vallecular collenchyma. It crosses with Equisetum hyemale (E. X ferrissii), which see for details.
This species is an annual in Canada and the northern United States, but is perennial in Mexico.A
This species is an annual in Canada and the northern United States, but is perennial in Mexico.A