Dryopteris rossii C.Chr.
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Authority
Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
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Family
Dryopteridaceae
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Scientific Name
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Description
Species Description - Rhizomes short-creeping; rhizome scales concolorous, blackish brown, lustrous, 2.5-5 x 1-2 mm, ovate, margins entire or with minute glands; fronds 20-80 cm long; stipes stramineous to castaneous proximally, 10-33 cm x 1-3(-4) mm, 1/3-1/2 the frond length, densely glandular, bases scaly, with entire scales 5-6(-10) x 1-2 mm, at least some scales bicolorous with lustrous dark tips and pale brown bases; blades chartaceous, green, deltate, 2-3-pinnate-pinnatifid at bases, otherwise mostly 2-pinnatepinnatifid, 25-44 x (8-)18-30 cm, with pinnae mostly alternate, ascending 50-65º from rachises, 10-15 pairs; rachises stramineous, with sparse, pale scales, also densely glandular; proximal pinnae ± equilateral to usually a little inequilateral, 8-20(-25) x 4-7(-10) cm, with larger basiscopic basal pinnule 3-5.5 cm long, acroscopic basal pinnule 2-3(-5) cm long; distal pinnae stalked to 8 mm, equilateral or often slightly more developed acroscopically, pinnules and ultimate segments toothed; indument abaxially of stipitate glands on costae, veins, and surfaces between veins, also with sparse, hair-like scales 0.5-1 mm long on costae, adaxially glabrous or the lamina quite glandular; sori submarginal, indusia brown to tan, 0.5-0.8(-1) mm diam., flat, glandular; 2n=82 (Edo. Méx., reported as D. patula by Mickel et al., 1966).
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Discussion
Dryopteris patula (Sw.) Underw. var. rossii (C. Chr.) C. Chr., Kongel. Danske Vidensk. Selsk. Skr., Naturvidensk. Math. Afd., ser. 7, 10: 20. 1913. Lectotype (chosen by Christensen, 1913: 22). Mexico. Morelos: Cuernavaca, Santa Mari´a, Ross 279 (M; isolectotype P!).
Unverified, Doubtful, or Mistaken Reports. DF (reported by Mickel & Beitel, 1988, but not verified). Qro (Carranza 1275, IEB, QMEX, cited by Di´az-Barriga & Palacios-Rios, 1992, and by Arregui ´n et al., 2001, but this specimen is D. cinnamomea). This distinctive species in the D. patula complex is common in western and central Mexico, but rare or absent elsewhere. It can be distinguished by its broadly deltate blades, generally longer-stalked pinnae, dark brown or blackish, lustrous, relatively small rhizome scales, and strongly bicolorous stipe scales with tan bases and black tips. The closest relative is D. knoblochii, which differs in the concolorous tan stipe base scales.
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Distribution
Terrestrial in pine-oak woodlands, especially along streams; (500-)900-2600 m. Mexico; also cited from Nicaragua and Costa Rica by Moran (in Davidse et al., 1995), but the provenance and/or identity of these collections is suspect.
Mexico North America| Nicaragua Central America| Costa Rica South America|