Polystichum orbiculatum (Desv.) J.Rémy & Fée
-
Authority
Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
-
Family
Dryopteridaceae
-
Scientific Name
-
Description
Species Description - Caudices mostly (1–)2–5 cm diam.; fronds to ca. 45 cm long; stipes (8–)12–22 cm long, 1–3 mm diam., 1/3 to nearly equaling the blade length; stipe bases with concolorous, brownish to tan or orangish, ovate-to lanceolate scales, larger ones to 15 x 3(–5) mm, ciliate and also denticulate, the scales similar to but paler than those of rhizome apices, distally with similar but fewer scales, but still rather densely scaly; blades subcoriaceous to coriaceous, 15–30 x (2–)3–6 cm, broadest at bases or nearly so, very gradually reduced at apices; rachises moderately to often densely scaly, scales lanceolate, ciliate and denticulate, to ca. 5 mm long, lacking buds; pinnae pinnate, ca. 25–40 pairs, often strongly ascending and imbricate, mostly 1.5–3(–4) x 1–1.5 cm, pinnules strongly revolute, rounded to oblong or obovate, non-auriculate, not aristate along margins and only faintly so at tips; indument abaxially along costae, costules, and veins of scattered, hair-like to lanceolate scales; sori exindusiate, often confluent at maturity; 2n=164 (CR).
-
Discussion
Aspidium orbiculatum Desv., Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 5: 321. 1811. Type. “America australi.” Collector not known (P, Herb. Desv.; photos GH, US). Nephrodium polyphyllum C. Presl, Reliq. Haenk. 1(1): 37. 1825. Polystichum polyphyllum (C. Presl) C. Presl, Suppl. Tent. Pterid. 83. 1836. Type. Peru. Haenke s.n. (PR or PRC; photo BM or PR).
This high-elevation species is extremely polymorphic, especially in South America, and is known to hybridize with others in Costa Rica. There is the likelihood that the species in the sense recognized here and in other recent floras (Mesoamerica, Peru) is really a species complex. Tryon and Stolze (1991) recognized two varieties, but the sole variety in Mexico and Central America is var. orbiculatum. It differs from P. speciosissimum, the closest relative in Mexico, by the less dissected and narrower blades, lack of modified whitish segment margins, and by the proximal pinnae not or only very slightly reduced.
-
Distribution
Terrestrial, flat meadows and steep slopes with pine, juniper, and Buddleia; 3600–4200 m. Mexico; Guat, CR; Col, Ven, Ec, Peru, Bol.
Mexico North America| Bolivia South America| Peru South America| Amazonas Ecuador South America| Venezuela South America| Amazonas Colombia South America| Costa Rica South America| Guatemala Central America|