Ophioglossales

Ophioglossales
Ophioglossales
Botrychium lunaria
Scientific classification
Kingdom: Plantae
Division: Pteridophyta
Class: Psilotopsida
Order: Ophioglossales
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Families and Genera

Ophioglossales (lit. 'snake-tongue-plant') are a small group of pteridophyte plants. Traditionally they are included in the division Pteridophyta, the ferns, originally as a family and later as the order Ophioglossales. In some classifications this group is placed in a separate division, the Ophioglossophyta, but recent molecular systematic studies have shown the Ophioglossales to be closely related to the Psilotales. The most recent classification by Smith et al. (2006) places these two orders together in class Psilotopsida.[1]

Ophioglossales contains a single family, Ophioglossaceae, which in some classifications is sometimes split into two or three families, the adders'-tongues, Ophioglossaceae, and the moonworts and grape-ferns, Botrychiaceae. The distinct species Helminthostachys zeylanica is sometimes given its own family, Helminthostachyaceae. A recently-discovered species and new genus, Mankyua chejuense, makes the picture more complicated. Most recent treatments of the Ophioglossoids have treated all of them in Ophioglossaceae.

The plants have short-lived spores formed in sporangia lacking an annulus, and borne on a stalk that splits from the leaf blade; and fleshy roots. Many species only send up one frond or leaf-blade per year. A few species send up the fertile spikes only, without any conventional leaf-blade. The gametophytes are subterranean. The spores will not germinate if exposed to sunlight, and the gametophyte can live some two decades without forming a sporophyte.

The genus Ophioglossum has the highest chromosome counts of any known plant. The record holder is Ophioglossum reticulatum, with about 630 pairs of chromosomes (1260 chromosomes per cell).[2]

References and external links

  1. ^ Smith, Alan R.; Kathleen M. Pryer, Eric Schuettpelz, Petra Korall, Harald Schneider, & Paul G. Wolf (2006). "A classification for extant ferns" (PDF). Taxon 55 (3): 705–731. doi:10.2307/25065646. JSTOR 25065646. http://www.pryerlab.net/publication/fichier749.pdf. 
  2. ^ Raven, Peter H., Ray F. Evert, & Susan E. Eichhorn, 2005. Biology of Plants, 7th edition. (New York: W. H. Freeman and Company). ISBN 0-7167-1007-2.

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Look at other dictionaries:

  • Ophioglossales — Ophioglossales …   Wikipédia en Français

  • Ophioglossales — prop. n. An order coextensive with the family {Ophioglossaceae}. Syn: order {Ophioglossales}. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • Ophioglossales — Ophioglossales, ca. 80 Arten umfassende eusporangiate Ordnung der ⇒ Polypodiopsida. Die im oberen Abschnitt der Raumwedel liegenden Sporangien haben keinen Anulus. Das Prothallium ist unterirdisch und mycotroph (Symbiose mit Pilzen). Ophioglossum …   Deutsch wörterbuch der biologie

  • Ophioglossales — Ophioglossales …   Wikipédia en Français

  • Ophioglossales — Natternzungengewächse Echte Mondraute (Botrychium lunaria; rechts) und Gewöhnliche Natternzunge (Ophioglossum vulgatum) Systematik …   Deutsch Wikipedia

  • Ophioglossales — noun coextensive with the family Ophioglossaceae • Syn: ↑order Ophioglossales • Hypernyms: ↑plant order • Member Holonyms: ↑Filicopsida, ↑class Filicopsida, ↑Filicinae, ↑ …   Useful english dictionary

  • ophioglossales — ophio·glos·sa·les …   English syllables

  • order Ophioglossales — noun coextensive with the family Ophioglossaceae • Syn: ↑Ophioglossales • Hypernyms: ↑plant order • Member Holonyms: ↑Filicopsida, ↑class Filicopsida, ↑Filicinae, ↑class Fili …   Useful english dictionary

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  • Filicophyta — Pour les articles homonymes, voir la ville de Fougères …   Wikipédia en Français

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