Polystichum hartwegii (Klotzsch) Hieron.

  • Authority

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

  • Family

    Dryopteridaceae

  • Scientific Name

    Polystichum hartwegii (Klotzsch) Hieron.

  • Description

    Species Description - Caudices mostly 2–4(–6) cm diam.; fronds mostly (60–)80– 140 cm long; stipes 20–45 cm long, 3–7 mm diam., ca. 1/3–1/2 the blade length; stipe bases with lanceate scales 8–15(–20) x 1–3(–5) mm, entire to denticulate or sparsely ciliate, concolorous and brown to bicolorous and with a broad, dark brown or blackish medial band and tan margins; blades chartaceous to subcoriaceous, 35–90 x (15–)25–55 cm, broadest at the bases or nearly so, attenuate at apices; rachises lacking buds, with brownish to tan, lanceolate and mostly hair-like scales; pinnae pinnate or often pinnate-pinnatifid, mostly 25–30 pairs, 10–25(–30) x 2–3.5(–5) cm, pinnules often pinnatifid or with a ± free obovate lobe at bases, both margins and tips spinulose, margins not revolute; indument abaxially along costae and costules of fibrillose scales; sori indusiate, confluent at maturity or not, indusia tan to brown (whitish when young), mostly 0.8–1.5 mm diam.; 2n=82 (Chis).

  • Discussion

    Aspidium hartwegii Klotzsch, Linnaea 20: 366. 1847. Type. Guatemala. “In montibus Las Nubes, prope Urbam” [near Guatemala City], Hartweg 631 (B!; isotypes BM!, K!, P!-2 sheets). Polystichum grande Fe´e, Me´m. Foug. 8: 98. 1857. Type. Mexico. Veracruz: Huatusco, Schaffner 217 (not found at P; probable isotype K labeled “Orizaba”). Polystichum drepanoides E. Fourn., Mexic. Pl. 1: 92. 1872. Type. Mexico. Chiapas: “inter San Bartolo et Pueblo-Novo,” Linden s.n. (P! photos US!). Aspidium trejoi Christ, Bull. Herb. Boissier, se´r. 2, 5: 255. 1905. Polystichum trejoi (Christ) Christ, Bull. Herb. Boissier, se´r. 2, 5: 728. 1905. Lectotype (chosen by Smith, 1981: 197). Mexico. Chiapas: San Pablo, Mu¨nch 167 (not found at P; isolectotype DS!).

    This species and P. rachichlaena are perhaps the most common polystichums in Mexico. The deeply incised pinnules, weakly bicolorous scales 8–15(–20)mmlong with ciliate margins, slightly reduced proximal pinna pair, and relatively large indusia mostly 0.8–1.5 mm diam. separate P. hartwegii from P. rachichlaena, P. erythrosorum, P. distans, and P. ordinatum. Polystichum turrialbae differs in having smaller indusia and pale brown, ovate rhizome scales with erose-denticulate margins. See P. fournieri for discussion of differences with that species. Polystichum drepanoides has been distinguished (e.g., by Smith, 1981) primarily by the larger and broader pinnae (to 30 x 3–5 cm) and entire indusia. We no longer consider these differences taxonomically significant and choose to synonymize this name under P. hartwegii. Many specimens, especially those from western Mexico, are slightly dimorphic, with the fertile pinnae narrower and with smaller pinnules than sterile pinnae. In general, in P. hartwegii and perhaps in other Mexican Polystichums, the fertile blades are more dissected than sterile blades on a given plant, but there is considerable variation in blade size and dissection. Plants from Colima and the Revillagigedo Islands (Isla Socorro, as well as some from the states of Sinaloa, Nayarit, and Jalisco) are the most aberrant of all and are placed here tentatively. They grow at the lowest elevation for the species (700 m on Socorro). Some specimens are nearly 3-pinnate. They have dark brown, concolorous stipe base scales but are otherwise similar to P. distans; they also often have rather glandular indusia. Vasquez V. 540 (NY, UC), from Colima, and McVaugh & Koelz 1004 (IEB, NY), from Jalisco, have irregularly shaped spores that may indicate hybridity. Specimens from Guerrero (e.g., Marti´nez S. 5068, ENCB, XAL; Rzedowski & McVaugh 30, MEXU, NY) tend to have rather sharply bicolorous scales (dark brown medial stripe, tan margins) and very large pinnae, to 28 x 5 cm; they have often been named P. drepanoides (e.g., by Lorea-Herna´ndez & Vela´zquez M., 1998). Two specimens from Oaxaca, Mickel 3728, 4678 (NY), are intermediate between P. hartwegii and P. ordinatum, and may represent hybrids. Ortega & Calzada 778 (XAL) has irregularly formed spores but looks reasonably typical for P. hartwegii. Polystichum hartwegii is recorded from Nuevo Leo´n by Hinton and Hinton (1995), but the specimen cited (Hinton 22654, TEX) needs verification.

  • Distribution

    Terrestrial in wet forests; (700–)1200–2500 m. Mexico; Guat, Hond, Salv, CR, Pan; Col?, Ven, Ec, Bol. Also cited from Nicaragua by Barrington (in Davidse et al., 1995).

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