Polystichum ordinatum (Kunze) Liebm.

  • Authority

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

  • Family

    Dryopteridaceae

  • Scientific Name

    Polystichum ordinatum (Kunze) Liebm.

  • Description

    Species Description - Rhizome erect; rhizome scales 7-12 mm long, 2-3 mm wide, bicolorous, center dark brown with margin narrow, light brown, ciliate; fronds clumped; stipe 10-25 cm long, ca. ¼ the frond length, densely scaly, scales ascending, narrowly lanceolate, ca. 1.5 cm long, 1-2 mm wide, entire, distinctly and sharply bicolorous, margin stramineous to tan, center dark brown; blade bipin-nate-pinnatisect, 30-90 cm long, 14-28 cm wide, rather thin, chartaceous; rachis not proliferous, minutely scaly or fibrillose-scaly, scales stramineous to brownish, entire but base dilated and minutely fimbriate; pinnae 32-42 pairs, lanceolate, to 15 cm long, 2.4 cm wide, lowermost 58 pairs gradually reduced (lowermost pair 1/3-2/3 the length of longest pairs); pinnules to ca. 25 pairs per pinna, the largest (basal) to 1.5 cm long, 6 mm wide, on acroscopic side deeply lobate to crenate, apex spinulose; costae below with scattered stramineous scales, costules and veins glabrous; sori not confluent at maturity; indusia 0.5-0.8 mm diam., tan to brownish.

  • Discussion

    Aspidium ordinatum Kunze, Linnaea 18: 347. 1844. Type. Mexico. Leibold s.n. [Leib. Verz. No. 39] (LZ, destroyed; presumed isotypes B!, K!, P!—6 sheets, NY!). Polystichum bicolor A. R. Smith, Proc. Calif. Acad. Sci. IV, 40: 223, f. 6E-G. 1975. Type. Mexico. Chiapas: Mun. Tenejapa, Colonia ‘Ach’lum, Ton 1987 (DS!). Polystichum ordinatum is distinctive in its narrowly lanceolate, bicolorous scales (7-12 mm long, 2-3 mm wide), greatly reduced basal pinnae, deeply serrate margin, and small indusia (0.5-0.8 mm). A. R. Smith (1981) believed the name P. ordinatum has been too widely applied and used it in a narrow sense. We follow that usage.

  • Distribution

    Terrestrial in wet forest; Ixtlán, Teotitlán; 2150-2700 m. Mexico (Ver, Oax, Chis); Guat.

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