Dryopteris rossii C.Chr.
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Authority
Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.
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Family
Dryopteridaceae
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Scientific Name
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Description
Species Description - Rhizome stout, erect, with lustrous, white crystals; rhizome scales blackish-brown, lustrous, concolorous, 2.5-3 mm long, 1-1.5 mm wide, ovate, entire with minute glands; fronds clumped; stipe 25-33 cm long, ½ the frond length, stramineous to castaneous to base, grooved, densely glandular scaly, with 5-6 mm long, scattered, bicolorous, entire scales with lustrous dark tips and pale brown basal 2/3; blade 25-44 cm long, 18-30 cm wide, tripinnate-pinnatifid at base, otherwise mostly bipinnate-pinnatifid, deflate; basal pinnae longest (8-13 cm long, 4-6.5 cm wide); rachis stramineous, densely glandular and with sparse, pale scales; pinnae linear-deltate, only basal pinnae with larger basiscopic basal pinnule (30-40 mm long), acroscopic basal pinnule shorter (20-28 mm long), other pinnae equilateral to exaggerated acroscopically; costae with dense glandular hairs, sparse, 0.5-1 mm long, hairlike scales; pinnules acute, toothed, thin-textured, with sparse glandular hairs on lower and upper surfaces, scales none, margin glandular; sori submarginal, indusia nearly round (round-reniform or cordate), 0.5-0.8(-l) mm wide, glandular, flat, brown to tan.
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Discussion
Dryopteris patula (Swartz) Underwood var. rossii (Christensen) Christensen, Kongel. Danske Vidensk. Selsk. Skr., Naturvidensk. Afd. VII, 10: 20. 1913. Lectotype (chosen by Christensen, 1913: 22). Mexico. Morelos: Cuernavaca, Santa Maria, Ross 279 (M; isolectotype P!). This distinctive species in the Dryopteris patula complex, found in the Pacific region of Oaxaca and the western states of Mexico, can be distinguished by its deflate frond, dark, small rhizome scales, strongly bicolorous stipe scales and sparse laminar glands. The dried rhizomes and rhizome scales are covered with sharp, fine, white crystals which may also be a species-specific character. The collections (3884, 6308) from Sola de Vega are from further east and at a higher elevation (1600-2150 m) than the other specimens. The stipe scales are not as strongly bicolorous as typical D. rossii and may represent another taxon. See discussion of D. glandulifera under D. cinnamomea.
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Distribution
Terrestrial on Pacific side; Putla, Sola de Vega; (500-)900-2150 m. Mexico (BC, Sin, Nay, Jal, Mich, Gro, Mex, Mor, DF, Oax).
Mexico North America|