Cystopteris fragilis (L.) Bernh.

  • Authority

    Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.

  • Family

    Cystopteridaceae

  • Scientific Name

    Cystopteris fragilis (L.) Bernh.

  • Description

    Species Description - Rhizomes short-creeping, not protruding past youngest leaves; rhizome scales brown, lanceolate, lustrous, membranous, entire, mixed with fine hairs; fronds to 47 cm long, clumped; stipes 1/3-1/2 the frond length, stramineous, often reddish brown and with scales at bases, glabrous or with scattered glandular hairs; blades (6-)9-20 x (2.5-)4-8 cm, bipinnate to tripinnate-pinnatifid, ovate-lanceolate with proximal 1-2 pairs of pinnae slightly shortened; rachises glabrous to pubescent with glandular hairs; pinnae 7-15 pairs, 1-4 cm long, thin, but more than 2 cells thick; segments oblong, 1.5-4 mm wide; veins ending in small emargination or in teeth; indusia glabrous with subentire to lacerate apices; 2n=168 (Chis).

  • Discussion

    Polypodium fragile L., Sp. Pl. 2: 1091. 1753. Type. Uncertain. See Blasdell (1963) for discussion of typification

    Polypodium diaphanum Bory, Voy. Iˆles Afrique 1: 328. 1804. Cystopteris fragilis (L.) Bernh. subsp. diaphana (Bory) Litard., Bull. Soc. Bot. Deux-Se`vres 23: 88. 1912. Cystopteris diaphana (Bory) Blasdell, Mem. Torrey Bot. Club 21(4): 47. 1963. Type. Re´union, Bory s.n. (P).

    Aspidium fragile (L.) Sw. var. fumarioides M. Martens & Galeotti, Me´m. Foug. Mexique 67. 1842. Type. Mexico. Temascal, Galeotti 6259 (BR!; isotype BR!, P!).

    Cystopteris acuta Fe´e, Me´m. Foug. 5: 300. 1852. Type. Mexico. [Veracruz:] Pic d’Orizaba, Galeotti 6260 (P!).

    Unverified, Doubtful, or Mistaken Reports. Ags (Siqueiros 4346, HUAA, and three other collections, cited by Siqueiros-Delgado & Gonza´lez-Adame, 2004, but not verified).

    Until the Mexican members of the Cystopteris fragilis complex have been studied and characterized to the degree that taxa northof Mexico have been (chromosomes, isozymes, etc.), a conservative treatment is followed, one that combines C. fragilis s.str. with C. diaphana. The North American taxa include diploids, allopolyploids, and various sterile hybrids, with species often having limited ranges. Cystopteris reevesiana Lellinger of the southwestern United States probably occurs in northern Mexico but is not readily distinguishable from Mexican C. fragilis and is not treated here. It is supposed to be distinguished from C. fragilis by blades bipinnate-pinnatifid to tripinnate (vs. pinnatepinnatifid to bipinnate-pinnatifid) and rhizomes usually longcreeping (vs. short-creeping). These characters do not seem to be correlated in Mexican specimens, and more work is needed to circumscribe the species. Cystopteris fragilis most closely resembles a small Dryopteris, but the hood-like indusia of the former readily distinguish it.

    Description and ecology - Terrestrial, often on or among rocks, on mossy ledges, fir forests, tropical deciduous forests, oak forests, montane cloud forests, pine-oak forests; (600–)1050–3400(–4050) m. Northern and western North America; Mexico; Guat, Hond, Salv, Nic, CR, Pan; Gr Ant; Col, Ven, Ec, Peru, Braz, Bol, Chile, J Fdez, Arg; Europe, Africa, Asia, Hawaii.