Ophioglossum

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Ophioglossum
Ophioglossum closeup.jpg
Ophioglossum
Scientific classification e
Kingdom: Plantae
Class: Polypodiopsida
Order: Ophioglossales
Family: Ophioglossaceae
Subfamily: Ophioglossoideae
Genus: Ophioglossum
L.
Species

Some 25-30, including:
Ophioglossum austroasiaticum
Ophioglossum azoricum
Ophioglossum californicum
Ophioglossum costatum
Ophioglossum crotalophoroides
Ophioglossum engelmannii
Ophioglossum lusitanicum
Ophioglossum nudicaule
Ophioglossum pedunculosum
Ophioglossum petiolatum
Ophioglossum polyphyllum
Ophioglossum pusillum
Ophioglossum pycnosticum
Ophioglossum reticulatum
Ophioglossum tenerum
Ophioglossum thermale
Ophioglossum vulgatum

Ophioglossum, the adder's-tongue ferns, is a genus of about 25–30 species of ferns in the family Ophioglossaceae, of the order Ophioglossales. The name Ophioglossum comes from the Greek, and means "snake-tongue";[1] the genus has the largest number of chromosomes in the known plant kingdom, but contrary to popular belief does not have the largest number of chromosomes out of all known organisms, falling short to the protist Oxytricha trifallax.

Their cosmopolitan distribution is mainly in tropical and subtropical habitats.[1]

Description[edit]

Adders-tongues are so-called because the spore-bearing stalk is thought to resemble a snake's tongue; each plant typically sends up a small, undivided leaf blade with netted venation, and the spore stalk forks from the leaf stalk, terminating in sporangia which are partially concealed within a structure with slitted sides.[1]

When the leaf blade is present, there is not always a spore stalk present, and the plants do not always send up a leaf, sometimes going for a year to a period of years living only under the soil, nourished by association with soil fungi.

The plant grows from a central, budding, fleshy structure with fleshy, radiating roots.

Taxonomy[edit]

Ophioglossum has a high chromosome count in comparison to other species, with 120 or up to 720 chromosomes possible in intervals of 120 due to polyploidy (multiple possible copies of chromosomes), it has almost 1260 number of chromosomes in the meiocyte (gamete mother cell) which undergo meiosis, the reduction division to form the gamete with only one set of chromosome getting incorporated into each gamete. [2]

Selected species[edit]

Species of Ophioglossum include:

References[edit]

  1. ^ a b c eFloras: Ophioglossum . accessed 2.14.2014.
  2. ^ Lukhtanov, Vladimir (2015-07-10). "The blue butterfly Polyommatus (Plebicula) atlanticus (Lepidoptera, Lycaenidae) holds the record of the highest number of chromosomes in the non-polyploid eukaryotic organisms". Comparative Cytogenetics. 9 (4): 683–690. doi:10.3897/compcytogen.v9i4.5760. PMC 4698580.

External links[edit]