Nephrolepis biserrata (Sw.) Schott

  • Authority

    Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

  • Family

    Nephrolepidaceae

  • Scientific Name

    Nephrolepis biserrata (Sw.) Schott

  • Description

    Species Description - Rhizome suberect to erect, stout, lacking tubers; rhizome scales concolorous, pale brown to orange, lanceolate, 5-7 mm long; fronds clumped, erect to arching; stipe light brown, 20-30 cm long, filiform-scaly to glabrescent; blade linear-elliptic, 75-100(-200) cm long, (11-) 16-24 cm wide, once-pinnate; rachis stramineous to tan, filiform-scaly with dense, fibrillose scales, 1-2 mm long, upper surface with catenate hairs; pinnae short-stalked, ± equally cuneate to equally auriculate at base, (5-)8.5-20 cm long, 9-20 mm wide, apex of longer pinnae with acuminate apex, margin finely serrulate (sterile blades) to crenate or bi-crenate (fertile blades); leaf tissue firm-herbaceous, finely hirtellous beneath with 0.3-0.6 mm long catenate hairs and scattered to dense, tan, fibrillose scales, especially on costae, upper surface with dense 0.3 mm long catenate hairs on costae; lime-dotted hydathodes on upper surface; sori round-reniform, mostly facing pinna margin, the sinus narrow, mature sporangia projecting on all sides; indusia brown, 0.8-1 mm wide, with 1-several 0.1-0.3 mm long hairs, entire margin.

  • Discussion

    Aspidium biserratum Swartz, J. Bot (Schrader) 1800(2): 32. 1801. Type. Mauritius. Grõndal (S). Nephrolepis mollis Rosenstock, Repert. Spec. Nov. Regni Veg. 22: 13. 1925. Type. Costa Rica. Brade 141 [Rosenstock exsicc. 289] (S?; isotype UC). The round-reniform indusia with occasional hairs, pinnae with hairs on the adaxial costae and abaxial lamina, and concolorous, spreading rhizome and stipe scales distinguish this taxon. See key for comparison with N. multiflora, seemingly a recent introduction. In Florida and Jamaica N. biserrata hybridizes with N. exaltata to produce an abortive-spored hybrid, N. x averyi Nauman (Amer. Fern J. 69: 69. 1979). Occurring in mixed colonies of its parents, it is larger than N. exaltata and has sparse adaxial hairs; the latter is narrower than N. biserrata and has falcate pinnae with only sparse adaxial hairs.

  • Distribution

    Terrestrial, epipetric or epiphytic; Choapan, Ixtlán; ca. 800 m [350 m in Chiapas (A. R. Smith, 1981)]. Mexico (Nay, Ver, Pue, Oax, Chis, Tab); US (Fla); Guat to Pan; WI, Trin; Col to Sur, to Peru & Braz; Old World tropics.

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