Adiantum L.
Descripción
Rhizomes short- to long-creeping or suberect, scaly; fronds small to large, usually monomorphic; stipes castaneous to atropurpureous, lustrous, glabrous to densely covered with narrow scales or hairs, brittle; blades simple to 5 times pinnate (or pedate); ultimate divisions (pinnae, pinnules, or pinnulets, depending on blade dissection) often rhomboidal, trapezoidal, or flabellate, sessile to short-petiolulate, never adnate, deciduous (articulate) in some species; laminae generally glabrous, sometimes glaucous, some species with stiff hairs or hairlike scales on the blades; veins free, forking, rarely anastomosing, sometimes with linear epidermal idioblasts (false veins) between the true veins; sporangia borne on the veins of recurved, membranous margins, indusia (and thus also sori) reniform to shortoblong to linear, lunate, or arcuate, one to usually several per ultimate division; paraphyses absent; spores tetrahedral, usually tan to yellowish; x=29, 30.A
Forma de vida
TerrestreA
Distribución
México (Country) native and not endemicB
Ecología y Hábitat
(Adiantum species grow mostly at low to middle elevations in wet forests; one ((A. capillusveneris) is pantropical and subtropical in moist microhabitats in otherwise dry regions. (Adiantum andicola and (A. poiretii generally occur at middle and high elevations, above the elevation of most other adiantums.A
Categoría IUCN
No incluidaC
Categoría NOM-059-SEMARNAT-2010
No incluidaD
Discusión taxonómica
Characters important in grouping and keying the species include the branching pattern of the blades (pinnate or imparipinnate; with or without a conform terminal pinna), degree of division of blades (pinnate, 2-pinnate, or more divided), presence or absence of venuloid idioblasts (epidermal false “veins”), shape of the ultimate divisions (whether dimidiate or flabellate), indument of blades and axes (whether of hairs, scales, or neither), scale margins (entire, denticulate, or ciliate), venation (free or anastomosing), vein ends (whether in teeth or sinuses), and presence or absence of articulation zones at the bases of the ultimate divisions. This last feature is presumably an adaptation to periodically drier habitats. The affinities of (Adiantum are with genera of Pteridaceae, but the genus is clearly somewhat isolated and is often treated in a family of its own, Adiantaceae, or in its own subfamily, Adiantoideae, within Pteridaceae (e.g., by R. Tryon et al. in Kubitzki, 1990). In most published trees, (Adiantum is sister to the vittarioid ferns, which are usually treated as a separate family Vittariaceae (e.g., Hasebe et al., 1995; Cranfill, unpubl. data). Sori are borne on the veins (and, reportedly, between the veins) of the strongly recurved and highly modified margins (false indusia), so that the sporangial capsules oppose the abaxial blade surfaces. This character is an autapomorphy for the genus. The indusia may be either round-reniform, lunate, oblong, or linear.
Excluded Species
Adiantum fructuosum Kunze ex Spreng., Syst. Veg. 4: 113. 1827. Adiantum tetraphyllum var. majus E. Fourn., Mexic. Pl. 1: 129. 1872. (a renaming of A. fructuosum Kunze, and so based on the type of that name; see Lellinger, Proc. Biol. Soc. Wash. 89: 704. 1977). Type. Cuba. Poeppig [209] (isotypes B–photo UC!, L–photo UC!, US!– photo UC!, frag. NY!).
This is very closely related to and possibly conspecific with A. tetraphyllum, with which it has been combined by several authors (e.g., Stolze, 1981; R. Tryon & Stolze, 1989). Other close relatives are A. amblyopteridium, A. oaxacanum, and A. trichochlaenum. Most likely, hybridization is occurring among species of this group of Adiantum, wherever they occur together.
Mexico has been included in the range of A. fructuosum by many authors (e.g., Smith, 1981; Palacios-Rios, 1992). Aside from problems distinguishing it from A. tetraphyllum, there are questions whether Mexican material is really conspecific with the Cuban type. We now believe that most or all specimens so named from Mexico are other species. For example, the specimens cited by Smith (1981) are either A. trichochlaenum (e.g., Breedlove 38511, DS) or A. tetraphyllum (e.g., Breedlove 22184, 22276, 26354A, 31511, 38582, 39999, DS). Specimens cited from Veracruz by Palacios Rios (1992) seem to be mostly, if not entirely, A. tetraphyllum (e.g., Purpus 2930, UC; this number, in different herbaria, cited as both species by Palacios Rios).
Adiantum fructuosum has been attributed a wide range by those who have dealt with it, from Mexico, Guatemala, Belize, Nicaragua, Costa Rica, Panama, Greater Antilles, Colombia, Venezuela, Trinidad, Guianas, Ecuador, Peru, Brazil, and Bolivia (see Lellinger, 1989; Jermy in Davidse et al., 1995). Specimens seen from Guatemala, Nicaragua, Costa Rica, and Panama seem to match the Cuban type well.
A
Excluded Species
Adiantum fructuosum Kunze ex Spreng., Syst. Veg. 4: 113. 1827. Adiantum tetraphyllum var. majus E. Fourn., Mexic. Pl. 1: 129. 1872. (a renaming of A. fructuosum Kunze, and so based on the type of that name; see Lellinger, Proc. Biol. Soc. Wash. 89: 704. 1977). Type. Cuba. Poeppig [209] (isotypes B–photo UC!, L–photo UC!, US!– photo UC!, frag. NY!).
This is very closely related to and possibly conspecific with A. tetraphyllum, with which it has been combined by several authors (e.g., Stolze, 1981; R. Tryon & Stolze, 1989). Other close relatives are A. amblyopteridium, A. oaxacanum, and A. trichochlaenum. Most likely, hybridization is occurring among species of this group of Adiantum, wherever they occur together.
Mexico has been included in the range of A. fructuosum by many authors (e.g., Smith, 1981; Palacios-Rios, 1992). Aside from problems distinguishing it from A. tetraphyllum, there are questions whether Mexican material is really conspecific with the Cuban type. We now believe that most or all specimens so named from Mexico are other species. For example, the specimens cited by Smith (1981) are either A. trichochlaenum (e.g., Breedlove 38511, DS) or A. tetraphyllum (e.g., Breedlove 22184, 22276, 26354A, 31511, 38582, 39999, DS). Specimens cited from Veracruz by Palacios Rios (1992) seem to be mostly, if not entirely, A. tetraphyllum (e.g., Purpus 2930, UC; this number, in different herbaria, cited as both species by Palacios Rios).
Adiantum fructuosum has been attributed a wide range by those who have dealt with it, from Mexico, Guatemala, Belize, Nicaragua, Costa Rica, Panama, Greater Antilles, Colombia, Venezuela, Trinidad, Guianas, Ecuador, Peru, Brazil, and Bolivia (see Lellinger, 1989; Jermy in Davidse et al., 1995). Specimens seen from Guatemala, Nicaragua, Costa Rica, and Panama seem to match the Cuban type well.
A