Ophioglossales

Ophioglossales is an order of ferns that belongs to the class Ophioglossopsida. This order is characterized by its unique reproductive structures, which differ significantly from those of most other ferns. The name Ophioglossales comes from the Greek words "ophis" meaning snake and "glossa" meaning tongue, referring to the shape of the fertile frond.

Members of Ophioglossales typically have a single fertile spike-like frond and a sterile vegetative frond. The fertile frond is where spore production occurs, and it often resembles a snake's tongue or a adder's tongue, hence the common names "adder's-tongue ferns" and "moonworts." The sterile frond is photosynthetic and is responsible for the plant's energy production.

Reproduction in Ophioglossales is through spores, as with other ferns. However, the development of their sporangia and the life cycle are distinct. The gametophyte generation is subterranean, saprophytic, and often long-lived, remaining undeveloped for many years before producing gametes. This unusual life cycle and morphology have led to their classification in a separate order.

The order Ophioglossales is relatively small, containing only a few genera such as Ophioglossum (adder's-tongues) and Botrychium (moonworts). These ferns are found in a variety of habitats worldwide, often in moist or woodland environments. Despite their unique biology, they are considered primitive among ferns.