Notholaena (from Ancient Greek νόθο(ς) + χλαῖνα), cloak fern,[1] is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae.[2] 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 secretion 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. Members of the related Pentagramma genus have a similar lower leaf-surface farina.
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.
As of January 2020, the Checklist of Ferns and Lycophytes of the World recognized the following species:[3]
Notholaena (from Ancient Greek νόθο(ς) + χλαῖνα), cloak fern, is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae. 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 secretion 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. Members of the related Pentagramma genus have a similar lower leaf-surface farina.
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.
Notholaena es un género con 243 especies descritas y 38 aceptadas de helechos queilantoides, perteneciente a la familia Pteridaceae.
Son helechos con rizoma brevemente rastrero a erecto, escamoso; hojas 1-2-pinnado-pinnatífidas, monomorfas, coriáceas; pecíolo con un haz vascular, pardo-amarillento a negruzco; lámina con el ápice pinnatífido, las pinnas con pínnulas adnatas o sésiles, blancas o amarillo farinosas en el envés, a menudo escamosas y/o pilosas, los márgenes aplanados o escasamente revolutos, relativamente sin modificaciones (en textura y color); raquis pardo-amarillento a negruzco, glabro a puberulento o farinoso; nervaduras libres, ramificadas o no, terminando en puntas un tanto claviformes; soros intramarginales, terminales en las nervaduras; esporas triletes, negruzcas, granuladas a crestadas; el número cromosomático es de: x=30.[1]
Se encuentra en Estados Unidos, México, Mesoamérica, Sudamérica y las Antillas.
Notholaena es tratada aquí en un sentido estricto. Algunas especies ubicadas anteriormente en el género por otros autores han sido trasferidas a Cheilanthes o Argyrochosma. Además, actualmente existe una controversia acerca de la tipificación correcta de Notholaena. Este escrito se apega a Tryon y Tryon (1982) quienes sugirieron a Notholaena trichomanoides (L.) Desv. como el lectotipo; sin embargo, Pic.Serm. (1983, 1989) presentó una fuerte evidencia de que Notholaena marantae (L.) R. Br. es el lectotipo correcto. Si se sigue la tipificación de Pichi Sermolli, entonces las especies neotropicales requerirán de segregación en Chrysochosma (J. Sm.) Kümmerle, ya que N. marantae pertenece a un grupo no farinoso del Viejo Mundo, de helechos queilantoides no relacionados con los taxa del Nuevo Mundo. El centro de diversificación del género en el Nuevo Mundo es el Desierto de Chihuahua en el N. de México.[1]
Notholaena fue descrito por Robert Brown y publicado en Prodromus Florae Novae Hollandiae 145. 1810.[1] La especie tipo es: Notholaena marantae (L.) R. Br.
A continuación se brinda un listado de las especies del género Notholaena aceptadas hasta abril de 2012, ordenadas alfabéticamente. Para cada una se indica el nombre binomial seguido del autor, abreviado según las convenciones y usos.[2]
Notholaena es un género con 243 especies descritas y 38 aceptadas de helechos queilantoides, perteneciente a la familia Pteridaceae.
