Asplenium scolopendrium

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Asplenium scolopendrium
(PD) Photo: Jasper Wubs
Hart's tongue fern in a Dutch forest
Scientific classification
Kingdom: Plantae
Class: Pteropsida
Order: Filicales
Family: Aspleniaceae
Genus: Asplenium
Species: A. scolopendrium[1]
Subspecies: A. s. var. americanum Fernald

A. s. var. scolopendrium

Binomial name
Asplenium scolopendrium
Linnaeus (1753)
Synonyms
  • Phyllitis scolopendrium (L.) Newman
  • Scolopendrium officinale Sm

Hart's tongue fern (Asplenium scolopendrium) is a species of fern, which can easily be recognized by its large tongue-shaped leaves, also known as fronds. The fronds grow to 7 centimeters wide and may be more than 50 centimeters in length. It mainlly grows in forests which have an alkaline soil although it has also been found growing on walls and in sewer systems. In nature the species is relatively rare, but many cultivars are grown commercially.

Morphology

The fronds are simple, undivided (uncommon for ferns) and tongue shaped, while the basal end is heart-shaped and usually slightly broader. Young fronds are light green while older ones become darker. Mature individuals produce sori on the underside (abaxial) of their fronds in lines perpendicular to and on both sides of the ranchis (the part to which the laminar green tissue of the blade is attached)[1].

Life cycle

see also the main article on ferns

Hart's tongue fern is a homosporous species, which means that every spore can give rise to both a male and female gametophyte. The female gametophytes, or prothallia, produce antheridiogens which are a kind of pheromone. The antheridiogens spread through the surrounding soil and will induce other spores the germinate and become male. If no fertilization occurs the gametophytes of this species become bisexual, enabling self-fertilization within the haploid individual.

References

  1. 1.0 1.1 van der Meijden, R. 2005. Heukels' flora van Nederland (Dutch flora), 23rd edition. Wolters-Noordhoff Publishers, Groningen, the Netherlands. ISBN: 90 01 58344 X
(PD) Photo: Jasper Wubs
A Group of Hart's tongue ferns growing in a drainage ditch on the forest floor.
(CC) Photo: Jasper Wubs
A dried frond, the brown lines of sori are clearly visible. Upper right; upper side (adaxial) of the frond, lower tight; under side (abaxial). The inset to the left is a close up of the tip of the frond, showing the sori in more detail.