Notholaena
Encyclopedia
Notholaena is a genus of fern
s in the family Pteridaceae
found exclusively in the New World
. Ferns of this genus are mostly epipetric (growing on rock) or occurring in coarse, gravelly soils, and are most abundant and diverse in the mountain ranges of warm arid or semiarid regions. They typically have a creeping or erect rhizome
and leaves that are pinnatifid
to pinnate-pinnatifid with marginal sori
protected by a false indusium formed from the reflexed margin of the leaf. Members of Notholaena also have a coating of whitish or yellowish farina (a powdery wax that prevents desiccation) on the surfaces of the leaves. The farina is often limited to the abaxial (lower) leaf surface, but may occur on the adaxial (upper) leaf surface as well.
The similar genus Argyrochosma
also has farinose leaves, but in that genus the ultimate segments of the leaves have entire margins and *are distinctly stalked, whereas in Notholaena the ultimate segments are usually lobed or pinnatifid and sessile
or subsessile. Notholaena has in the past been used as a "catch-all" genus for a wide variety of species that did not fit well in other arid fern genera but it has more recently been defined in a much narrower sense, making the genus much more morphologically and evolutionarily coherent. The genera Argyrochosma
and Astrolepis
were recently segregated
from Notholaena, and other former members of Notholaena are now in the genus Cheilanthes.
Selected species
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...
found exclusively in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
. Ferns of this genus are mostly epipetric (growing on rock) or occurring in coarse, gravelly soils, and are most abundant and diverse in the mountain ranges of warm arid or semiarid regions. They typically have a creeping or erect 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...
and leaves that are pinnatifid
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...
to pinnate-pinnatifid with 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 margin of the leaf. Members of Notholaena also have a coating of whitish or yellowish farina (a powdery wax that prevents desiccation) on the surfaces of the leaves. The farina is often limited to the abaxial (lower) leaf surface, but may occur on the adaxial (upper) leaf surface as well.
The similar genus Argyrochosma
Argyrochosma
Argyrochosma is a genus of ferns known commonly as false cloak ferns. Species now in this genus were previously treated as members of related genera Notholaena or Pellaea but were segregated into their own genus in 1987. These ferns, of which there are about 20 species, are native to the Americas,...
also has farinose leaves, but in that genus the ultimate segments of the leaves have entire margins and *are distinctly stalked, whereas in Notholaena the ultimate segments are usually lobed or pinnatifid and sessile
Sessility (botany)
In botany, sessility is a characteristic of plants whose flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel...
or subsessile. Notholaena has in the past been used as a "catch-all" genus for a wide variety of species that did not fit well in other arid fern genera but it has more recently been defined in a much narrower sense, making the genus much more morphologically and evolutionarily coherent. The genera Argyrochosma
Argyrochosma
Argyrochosma is a genus of ferns known commonly as false cloak ferns. Species now in this genus were previously treated as members of related genera Notholaena or Pellaea but were segregated into their own genus in 1987. These ferns, of which there are about 20 species, are native to the Americas,...
and Astrolepis
Astrolepis
Astrolepis is a small genus of ferns in the family Pteridaceae. It was formed in 1992 from species previously placed in Cheilanthes and Notholaena. The name is derived from the Greek words ἄστρον , meaning "star," and λεπίς , meaning "scale," referring to the star-like scales on adaxial blade...
were recently segregated
Segregate (taxonomy)
In taxonomy, a segregate, or a segregate taxon is created when a taxon is split off, from another taxon. This other taxon will be better known, usually bigger, and will continue to exist, even after the segregate taxon has been split off...
from Notholaena, and other former members of Notholaena are now in the genus Cheilanthes.
Selected species
- Notholaena bryopoda – a species unusual among ferns in that it is endemicEndemic (ecology)Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to gypseousGypsumGypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
substrates in Mexico - Notholaena californicaNotholaena californicaNotholaena californica is a species of fern known by the common name California cloak fern. It is native to southern California, Arizona, and adjacent northwestern Mexico, where it grows in dry, rocky habitat types.-Description:...
– a fern of the southwestern US and northern Mexico - Notholaena grayi – a fern of igneous substrates in Mexico and the Madrean sky islandsMadrean sky islandsThe Madrean Sky Islands are enclaves of Madrean pine-oak woodlands, found at higher elevations in a complex of small mountain ranges in southern and southeastern Arizona, southwestern New Mexico, and northwestern Mexico. The sky islands are surrounded at lower elevations by the Sonoran and...
of the southwestern US - Notholaena marantae – occurs on dry rocks and serpentines in South and Central Europe
- Notholaena standleyi – a common fern of igneous substrates in the southwestern US