Ophioderma palmata

Hand fern
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Psilotopsida
Order:	Ophioglossales
Family:	Ophioglossaceae
Genus:	Ophioderma
Species:	O. palmata

Ophioderma palmata, variously known as hand fern, dwarf staghorn, or hand tongue, is a terrestrial, fern-like plant. The genus Ophioderma is in the family Ophioglossaceae of the order Ophioglossales, a small group of non-flowering vascular plants. The hand fern is an epiphyte, growing in old leaf bases of the Cabbage palmetto (Sabal palm). It is closely related to, and sometimes treated as a subgenus of, the genus Ophioglossum. It has long been known as Cheiroglossa palmata, but recent genetic analysis has determined that it should be treated in the genus Ophioderma.

The leaves are palmately lobed and roughly shaped like a hand. They grow up tp 30 cm wide and the margins are entire (no serration). The fertile fronds are a set of small tapering sporophores that bear the spores. There are several to many at the base of each leaf blade. On the sporophores are the sporangial clusters with sporangia in two rows, all embedded in compact, linear spikes. The main areoles large, usually more than 30 mm. The pale yellowish-brown roots are dichotomous. The gametophytes are brown to white, cylindric, and repeatedly branched.

This plant is found worldwide, but in the United States, it is restricted to the far southeast, primarily Florida. It has become rare in Florida due to overcollecting and extensive drainage of natural wetlands from development and water diversion projects. It is reported to not survive cultivation.

References

• Cheiroglossa palmata
• Photos and info on the Hand fern
• Cheiroglossa in Flora of North America]