Diplazium Sw.
Descripción
Roots stout and somewhat fleshy; rhizomes usually suberect to erect (caudices sometimes trunk-like), scaly; fronds medium-sized to often large, monomorphic, not articulate; stipes usually glabrous, scaly at bases, with two crescent-shaped vascular bundles in cross section; blades thin-herbaceous to chartaceous or subcoriaceous, usually pinnate to 2–3-pinnatepinnatifid, sometimes 4+-pinnate, rarely simple, some species producing buds in axils of blade bases, pinnae, or pinnules, these sometimes developing into plantlets; veins generally free, rarely casually to abundantly anastomosing, pinnate in the ultimate segments or sometimes strongly curved toward blade margins and appearing parallel; indument abaxially of brownish to tan scales on rachises, costae, and costules, sometimes also of hairs, these often septate, adaxially the blades glabrous or with short papillae or hairs ca. 0.1 mm (or less) in rachial, costal, and costular grooves; sori abaxial, linear or oblong on the veins, usually with at least some of them (sometimes only the basal ones) backto-back (diplazioid) on a single vein; indusia generally covering each sorus, rarely absent, paraphyses absent; sporangia shortstalked, stalks less than half the length of capsules; spores bilateral, with winged perispores; x=41.A
Forma de vida
TerrestreA
Distribución
México (país) Nativo y no endémicoA
Tipo de vegetación
Wet tropical forests. -no state-A
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Diplazium comprises 350–400 species, with probably more than 150 in the NewWorld; it is generally a genus of wet tropical forests of low to middle (rarely high) elevations. Twenty-five species are known from Mexico. Chromosome counts for species range from diploid, 2n=82, to octaploid, 2n=328. Judging by the number of intermediate specimens that show malformed spores and a few chromosome counts, hybridization is apparently common in the genus, at least in the Neotropics. Putative hybrids have been suggested between species in Ecuador (Stolze et al., 1994) and Mexico (Mickel & Beitel, 1988; Smith, 1981). Monographic studies are needed for a better understanding of the species and their relationships. Diplazium is distinguished by its commonly indusiate sori (among Mexican species, indusia are absent, or nearly so, only in D. lindbergii) that are elongate and at least sometimes back-to-back along the veins, relatively thick roots, suberect to erect rhizomes, two ribbon-like vascular bundles in the petioles, and a chromosome base number of x=41. At least half of the Mexican species have distinctive papillae 0.05–0.1 mm long in the rachial, costal, and costular grooves adaxially.
Relationships of the genus are with the athyrioid ferns, especially. Athyrium and a number of Old World genera usually now segregated from Diplazium and Athyrium, e.g., Callipteris, Cornopteris, and Deparia. Diplazium has more distant relationships with Onocleopsis and the onocleoid ferns, and, beyond that, with the blechnoid ferns (Cranfill, unpubl.).
Unplaced Names
Diplazium anthraxacolepis Fée, Mém. Foug. 8: 84. 1857. Syntypes. Mexico. Veracruz: Huatusco, Schaffner 267b, 627a (RB).
Diplazium feei Schaffner ex Fée, Mém. Foug. 8: 85. 1857. Type. Mexico. Veracruz: barrancas de San Martıín et de San Francisco, 2500 m, 1854, Schaffner 265 (RB, as cited by Windisch, Amer. Fern J. 72: 58. 1982). Schaffner s.n. (P!), bearing this name, is 2-pinnate and a little more, but less divided than D. expansum and glabrous abaxially.
Excluded Species
Diplazium falcatum Liebm., Mexic. Bregn. 253 (reprint 101). 1849, hom. illeg., non D. Don, 1825. Type. Mexico. Oaxaca: Teotalcingo, Chinantla, Liebmann s.n. [Pl. Mex. 2375, Fl. Mex. 361] (C!). Maxon, in 1929, annotated this specimen as “young Hemitelia sp.” We agree that it is Cyatheaceae, but cannot say what species it might be.
Diplazium pectinatum (Fée) C. Chr. in Urban, Symb. Antill. 9: 324. 1925. Hypochlamys pectinata Fée, Mém. Foug. 5: 200, t. 17C, f. 2. 1852. Type. Hispaniola. de Tussac s.n. (P?). Diplazium pectinatum (synonym Allantodia costalis Desv.) was included in the index for pteridophytes from Oaxaca (Mickel & Beitel, 1988: 551), but there is no mention of this species on the page cited (p. 159). It is closely related to D. lindbergii, but differs by the more deeply incised pinnae, with segments cut nearly to the costae, thinner blade texture, and segments spreading at a right angle to the costae. We find no other mention of the species having been recorded from Mexico or Central America. Diplazium pectinatum is confined to Jamaica and Hispaniola (Proctor, 1985), as generally construed.
Diplazium prominulum Maxon, Contr. U.S. Natl. Herb. 13: 15. 1909. Type. Guatemala. Baja Verapaz. Between Purulhá and Panzál, Türckheim II.1683 (US; isotype P!). Diplazium prominulum was cited from Chiapas (Smith, 1981; Smith in Breedlove 1986) on the basis of Breedlove 33658 (DS). Adams (in Davidse et al., 1995) redetermined this specimen as D. lonchophyllum, and we agree. The distribution of the species as currently known is Guat, Nic, CR, Pan; Ec (Stolze et al., 1994). Diplazium prominulum is similar to D. cristatum and D. lonchophyllum except: rhizomes erect, apices lacking scales; rachises yellowish, flexuous; blades subcoriaceous; segments rounded at tips, soriferous throughout their length; and veins free, prominent abaxially.
Diplazium villosum C. Presl, Suppl. Tent. Pterid. 114. 1836. The type was said by Presl to be from Mexico (Haenke s.n., probable isotypes BM!, K!, frag. NY!). This is not a Diplazium, but a juvenile specimen of a species of Cyatheaceae, probably Sphaeropteris, possibly S. integra (J. Sm.) R. M. Tryon, from the Philippines.
A
Relationships of the genus are with the athyrioid ferns, especially. Athyrium and a number of Old World genera usually now segregated from Diplazium and Athyrium, e.g., Callipteris, Cornopteris, and Deparia. Diplazium has more distant relationships with Onocleopsis and the onocleoid ferns, and, beyond that, with the blechnoid ferns (Cranfill, unpubl.).
Unplaced Names
Diplazium anthraxacolepis Fée, Mém. Foug. 8: 84. 1857. Syntypes. Mexico. Veracruz: Huatusco, Schaffner 267b, 627a (RB).
Diplazium feei Schaffner ex Fée, Mém. Foug. 8: 85. 1857. Type. Mexico. Veracruz: barrancas de San Martıín et de San Francisco, 2500 m, 1854, Schaffner 265 (RB, as cited by Windisch, Amer. Fern J. 72: 58. 1982). Schaffner s.n. (P!), bearing this name, is 2-pinnate and a little more, but less divided than D. expansum and glabrous abaxially.
Excluded Species
Diplazium falcatum Liebm., Mexic. Bregn. 253 (reprint 101). 1849, hom. illeg., non D. Don, 1825. Type. Mexico. Oaxaca: Teotalcingo, Chinantla, Liebmann s.n. [Pl. Mex. 2375, Fl. Mex. 361] (C!). Maxon, in 1929, annotated this specimen as “young Hemitelia sp.” We agree that it is Cyatheaceae, but cannot say what species it might be.
Diplazium pectinatum (Fée) C. Chr. in Urban, Symb. Antill. 9: 324. 1925. Hypochlamys pectinata Fée, Mém. Foug. 5: 200, t. 17C, f. 2. 1852. Type. Hispaniola. de Tussac s.n. (P?). Diplazium pectinatum (synonym Allantodia costalis Desv.) was included in the index for pteridophytes from Oaxaca (Mickel & Beitel, 1988: 551), but there is no mention of this species on the page cited (p. 159). It is closely related to D. lindbergii, but differs by the more deeply incised pinnae, with segments cut nearly to the costae, thinner blade texture, and segments spreading at a right angle to the costae. We find no other mention of the species having been recorded from Mexico or Central America. Diplazium pectinatum is confined to Jamaica and Hispaniola (Proctor, 1985), as generally construed.
Diplazium prominulum Maxon, Contr. U.S. Natl. Herb. 13: 15. 1909. Type. Guatemala. Baja Verapaz. Between Purulhá and Panzál, Türckheim II.1683 (US; isotype P!). Diplazium prominulum was cited from Chiapas (Smith, 1981; Smith in Breedlove 1986) on the basis of Breedlove 33658 (DS). Adams (in Davidse et al., 1995) redetermined this specimen as D. lonchophyllum, and we agree. The distribution of the species as currently known is Guat, Nic, CR, Pan; Ec (Stolze et al., 1994). Diplazium prominulum is similar to D. cristatum and D. lonchophyllum except: rhizomes erect, apices lacking scales; rachises yellowish, flexuous; blades subcoriaceous; segments rounded at tips, soriferous throughout their length; and veins free, prominent abaxially.
Diplazium villosum C. Presl, Suppl. Tent. Pterid. 114. 1836. The type was said by Presl to be from Mexico (Haenke s.n., probable isotypes BM!, K!, frag. NY!). This is not a Diplazium, but a juvenile specimen of a species of Cyatheaceae, probably Sphaeropteris, possibly S. integra (J. Sm.) R. M. Tryon, from the Philippines.
A
Bibliografía
C. SEMARNAT 2019: MODIFICACIÓN del Anexo Normativo III, Lista de especies en riesgo de la Norma Oficial Mexicana NOM-059-SEMARNAT-2010: 101 pp. – https://www.dof.gob.mx/nota_detalle.php?codigo=5578808&fecha=14/11/2019#gsc.tab=0 [accessed 2023-05-04 06:16]