Dryopteris arguta (Kaulf.) Watt

  • Authority

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

  • Family

    Dryopteridaceae

  • Scientific Name

    Dryopteris arguta (Kaulf.) Watt

  • Description

    Species Description - Rhizomes short-creeping to suberect; rhizome scales concolorous, orange-brown, lustrous, to 20 x 5 mm, ovate-lanceolate, entire, sometimes twisted; fronds 25–100 cm long; stipes tan, to 35 cm x 6 mm, 1/4–1/3 the frond length, densely scaly at bases and often distally, scales orange-brown to tan, ovate to lanceolate, lustrous, entire; blades herbaceous, green to yellow-green, ovate-lanceolate, pinnate-pinnatifid to 2-pinnate at bases, to 60 x 8–30 cm, pinnae spreading to slightly ascending ca. 70º from rachises, to 32 pairs; rachises stramineous to tan, with numerous persistent tan scales to ca. 6 x 1 mm, eglandular; proximal pinnae equilateral or the basiscopic segments slightly longer than the acroscopic ones, to ca. 14 x 3 cm,±the same length as adjacent several pinna pairs or only slightly reduced, largest pinnules to ca. 20 x 6 mm; distal pinnae sessile or stalked to 3 mm, equilateral or nearly so, to ca. 14 x 3.5 cm, pinnule margins serrate with spinulose teeth; indument abaxially of scattered lanceolate scales on costae and costules, veins and leaf tissue between veins glabrous, lacking glands, adaxially the surfaces essentially glabrous; sori medial, indusia brown, ca. 1–1.5 mmdiam., somewhat vaulted, glabrous; 2n=82 (USA).

  • Discussion

    Aspidium argutum Kaulf., Enum. Filic. 242. 1824. Type. U.S.A. California: Chamisso s.n. (LE?)

    Dryopteris arguta is a species of the western United States, barely ranging into northern Baja California Norte. Its closest affinities appear to be with D. pallida (Bory) C. Chr. ex Maire & Petitm., from Mediterranean Europe (see Fraser-Jenkins, 1986: 193). Of Mexican species, it is similar to D. filix-mas and differs from that primarily in the scalier stipes and rachises, less reduced proximal pinnae, and more strongly spinulose segments. There is also similarity to, and probably relationship with, D. maxonii, but the latter differs in having less scaly stipes and rachises, tan stipe scales, and ultimate segments not so distinctly toothed or spinulose at the tips. The combining authority for D. arguta is often given asWatt (Canad. Nat., II, 3: 159. 1866), but at this place Watt clearly chose to recognize Dryopteris as a subgenus (or subgroup) within Aspidium, and so Watt should not be credited with the species combination in Dryopteris.

  • Distribution

    Terrestrial in oak woodlands, rocky banks and canyons, and in sheltered caves; 50–400 m. Can (Brit Col), USA (Ariz, Calif, Oreg, Wash); Mexico.

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