Pellaea is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of fern

Fern

A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s in the family Pteridaceae

Pteridaceae

Pteridaceae is a large family of ferns in the order Pteridales. Members of the family have creeping or erect rhizomes and are mostly terrestrial or epipetric...

. The name is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 word πελλος (pellos), meaning "dark," and refers to the bluish-gray stems. Members of the genus are commonly known as cliffbrakes. They primarily grow in rocky habitats, including moist rocky canyons, slopes, and bluffs.

Distribution

They are most abundant and diverse in the southwestern United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 south into Andean

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, central and southern Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, and eastern Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 to New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

.

Description

They typically have creeping rhizome

Rhizome

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

s and pinnate

Pinnate

Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

ly to bipinnately compound leaves lacking prominent scales or trichome

Trichome

Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...

s on the blades. Like most members of Pteridales

Pteridales

The Pteridales are ferns that have their sori in linear strips under the edge of the leaf tissue, usually with the edge of the lamina reflexed over.This order is considered a family under the Smith classification...

, they have marginal sori

Sorus

A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....

 protected by a false indusium formed from the reflexed leaf margin.

The distinction of Pellaea from the typically hairier or scalier Cheilanthes has proven difficult, with some members (e.g., the African P. viridis) being of uncertain affinity, listed by different authors in both genera. Furthermore, Pellaea contains a number of sections that may warrant generic status since they appear to represent convergence

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

 in phenotype

Phenotype

A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

s related to arid habitats rather than similarity due to common descent. These sections are:

• Pellaea section Pellaea: includes most American members of the genus as well as a single African member (P. rufa);
• Pellaea section Ormopteris: includes three or four South American species in or near Brazil;
• Pellaea section Platyloma: includes the Australian and New Zealand species;
• Pellaea section Holcochlaena: includes the African species.

Members of the genus are not generally used for any commercial purpose, although several species (most notably P. rotundifolia

Pellaea rotundifolia

Pellaea rotundifolia. the Button fern, is a species of fern endemic to New Zealand, and often cultivated as a garden and house plant.Pellaea rotundifolia has round, dark-green, leathery leaves, on fronds up to about one foot in length....

and P. falcata

Pellaea falcata

Pellaea falcata, the Sickle Fern, is a widespread and common plant, growing in eastern Australia. Often seen in on the coast and ranges in eucalyptus forest and rainforest. Occurring in Tasmania, Victoria, New South Wales and Queensland. Also occurring on Lord Howe Island.Fronds usually 37 to...

of section Platyloma) are cultivated as indoor plants.

Species

Pellaea section Pellaea Pellaea atropurpurea Pellaea atropurpurea This is a fern, P. atropurpurea, commonly known as purple-stem cliffbrake or just purple cliffbrake. Brake is an old word for fern, related to the word bracken. Like many other members of the Pteridaceae, it is a rock plant, needing a calcareous substrate.P... (L.) Link – purple-stem cliffbrake Pellaea brachyptera Pellaea brachyptera Pellaea brachyptera is a species of fern known by the common name Sierra cliffbrake. It is native to the coastal and inland mountains of northern California and Oregon, and a disjunct population was discovered in Chelan County, Washington, in 1986.... (T.Moore) Baker – Sierra cliffbrake Pellaea breweri Pellaea breweri Pellaea breweri is a species of fern known by the common name Brewer's cliffbrake. It is native to much of the Western United States. It grows in rocky habitat such as cliffs and mountain slopes.-Description:... D.C.Eaton – Brewer's cliffbrake Pellaea bridgesii Pellaea bridgesii Pellaea bridgesii is a species of fern known by the common name Bridges' cliffbrake. It is native to an area of the western United States from northern California to Idaho, where it grows in rocky granitic cliffs and slopes.... Hook. – Bridges' cliffbrake Pellaea glabella Pellaea glabella Pellaea glabella is the smooth cliffbrake. For much of pteridological history, it was regarded as a reduced form or variety of Pellaea atropurpurea. P. glabella is known to exist in two cryptic species, one diploid and one tetraploid. The diploid reproduces sexually, while the tetraploid is... Mett. ex Kuhn – smooth cliffbrake Pellaea mucronata Pellaea mucronata Pellaea mucronata is a species of fern known by the common name Bird's foot cliffbrake.It is native to much of California, and parts of Oregon, Nevada, Arizona, and Baja California, where it grows in various types of rocky habitat. The subspecies californica is limited to California, while ssp... (D.C.Eaton) D.C.Eaton – birdfoot cliffbrake Pellaea wrightiana Hook. – Wright cliffbrake Pellaea truncata Pellaea truncata Pellaea truncata is a species of fern known by the common name spiny cliffbrake. It is native to the southwestern United States and northern Mexico, where it grows in rocky areas, such as cliffs and slopes.-Description:... Goodding – spiny cliffbrake Pellaea ovata (Desv.) Weatherby – ovateleaf cliffbrake Pellaea section Ormopteris

Pellaea cymbiformis Pellaea section Platyloma Pellaea rotundifolia Pellaea rotundifolia Pellaea rotundifolia. the Button fern, is a species of fern endemic to New Zealand, and often cultivated as a garden and house plant.Pellaea rotundifolia has round, dark-green, leathery leaves, on fronds up to about one foot in length.... (G.Forst.) Hook. Pellaea falcata Pellaea falcata Pellaea falcata, the Sickle Fern, is a widespread and common plant, growing in eastern Australia. Often seen in on the coast and ranges in eucalyptus forest and rainforest. Occurring in Tasmania, Victoria, New South Wales and Queensland. Also occurring on Lord Howe Island.Fronds usually 37 to... (R.Br.) Fée Pellaea calidirupium Pellaea calidirupium Pellaea calidirupium is a plant, of eastern Australia restricted to rock crevices in relatively arid environments. It is found in Tasmania where it is considered rare and is only found on the East Coast, the Midlands and lower slopes of the Centtral Plateau on dry rock faces... Pellaea section Holcochlaena Pellaea calomelanos Pellaea calomelanos Pellaea calomelanos is a species of fern. It is found in eastern and southern Africa where it is associated with Afromontane vegetation, as well as on Madagascar, The Comoros, and the Mascarene Islands... Pellaea dura Pellaea viridis (Forssk.) Prantl – green cliffbrake Pellaea boivinii