Eusporangiate ferns are vascular spore plants, whose sporangia arise from several epidermal cells

Epidermis (botany)

The epidermis is a single-layered group of cells that covers plants' leaves, flowers, roots and stems. It forms a boundary between the plant and the external environment. The epidermis serves several functions, it protects against water loss, regulates gas exchange, secretes metabolic compounds,...

 and not from a single cell as in leptosporangiate ferns. Typically these ferns have reduced root systems and sporangia that produce large amounts or spores (up to 7000 spores per sporangium in Christensenia

Christensenia

Christensenia is a genus of ferns in the botanical family Marattiaceae. The genus is confined to the Indo-Malayan region. The basal chromosome number for this genus is 2n=80....

)

There are two extant eusporangiate fern families: the Marattiaceae and Ophioglossaceae

Ophioglossaceae

Ophioglossaceae, the Adder's tongue family, is a family of ferns, currently thought to be most closely related to Psilotaceae, the two together comprising the class Psilotopsida as the sibling group to the rest of the ferns. The Ophioglossaceae is one of two groups of ferns traditionally known as...

, with a total of about 500 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

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