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Ophioglossum vulgatum
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Ophioglossales
Family: Ophioglossaceae
Subfamily: Ophioglossoideae
Genus: Ophioglossum
Type species
Ophioglossum vulgatum

See text

  • Cassiopteris H.Karst.
  • Goswamia Zhang & Zhang
  • Haukia Zhang & Zhang
  • Rhizoglossum Presl non Kylin
  • Whittieria Zhang & Zhang

Ophioglossum, the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The name Ophioglossum comes from the Greek meaning "snake-tongue".[3] Their cosmopolitan distribution is mainly in tropical and subtropical habitats.[3]

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 Sterkiella histriomuscorum.


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 slit sides.[3]

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.


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 (spore mother cell) which undergo meiosis, the reduction division to form the spore with only one set of chromosomes getting incorporated into each spore.[4]


Phylogeny of Ophioglossum[5][6]


O. polyphyllum

section Aitchisonii

O. engelmannii


O. nudicaule

O. rubellum

O. trilokinathii

O. gomezianum

O. costatum

O. eliminatum


O. crotalophoroides

Ophioglossum s.s.

O. parvifolium

O. kawamurae

O. parvum


O. pusillum

O. austroasiaticum

O. namegatae

O. lancifolium

O. petiolatum

O. coriaceum

O. reticulatum

O. thermale

O. gramineum

O. californicum

O. vulgatum



As of December 2021, World Ferns listed the following species:[2]

Species that may be placed in this genus include:[2]


  1. ^ "Ophioglossum". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 22 April 2020.
  2. ^ a b c Hassler, Michael (2004–2021). "Genus Ophioglossum L." World Ferns. Synonymic Checklist and Distribution of Ferns and Lycophytes of the World. Version 12.8. Retrieved 2021-12-22.
  3. ^ a b c eFloras: Ophioglossum accessed 14 February 2014.
  4. ^ 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. PMID 26753083.
  5. ^ Nitta, Joel H.; Schuettpelz, Eric; Ramírez-Barahona, Santiago; Iwasaki, Wataru; et al. (2022). "An Open and Continuously Updated Fern Tree of Life". Frontiers in Plant Science. 13: 909768. doi:10.3389/fpls.2022.909768. PMC 9449725. PMID 36092417.
  6. ^ "Tree viewer: interactive visualization of FTOL". FTOL v1.5.0 [GenBank release 256]. 2023. Retrieved 17 August 2023.

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