Ophioglossum

Ophioglossum
Ophioglossum vulgatum
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Psilotopsida
Order:	Ophioglossales
Family:	Ophioglossaceae
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 (adder's-tongue) is a genus of about 25-30 species of Ophioglossales in the family Ophioglossaceae, with a cosmopolitan but primarily tropical and subtropical distribution. The name Ophioglossum comes from the Greek, and means "snake-tongue".

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

Ophioglossum has the highest chromosome count of any known living organism, with 1,262 chromosomes. However, most species only have chromosomes in the 240-300+ range.

References

• Ophioglossum in Flora of North America

External links

• A description from Culpeper's "The English Physician" from 1814