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W. obtusa resources
Descriptive
inoperativewith endangered status account in Canada (link inoperative)
Distribution
North AmericaNorth America
Drawing
Britton & BrownBritton & Brown
Flora
Flora of North AmericaFlora of North America
Photo
fertile frondfertile frond
fertile pinnafertile pinna
fertile pinnafertile pinna
frond in habitat, Warren County, New Jerseyfrond in habitat, Warren County, New Jersey
frond upper surface, hydathodes out of focusfrond upper surface, hydathodes out of focus
habithabit
pair of frondspair of fronds

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Woodsia obtusa (Sprengel) Torr.

Blunt-lobed woodsia

Etymology Obtusa means blunt. The lobes of the indusium are blunt, as are the pinnules.
Description Rhizome: creeping to erect, scales brown, uniform and others with a dark central stripe.
Frond: 40 cm high by 8 cm wide, evergreen sterile fronds, fertile fronds dying back, monomorphic superficially, but the sterile fronds decline and remain green through winter, blade/stipe ratio: 2:1.
Stipe: persistent bases of unequal lengths, light brown or straw-colored when mature, occasionally darker at very base, scales tan, vascular bundles: 2, oblong, at an acute angle, at stipe base, merging above to a u-shape; the illustration below is not entirely in accord.
Blade: 2-pinnate-pinnatifid at base, rhombic, tapering to both ends, truncated at base, herbaceous, gray-green, glands on both surfaces, rachis, costa with glandular hairs and scattered, often hairlike scales.
Pinnae: 8 to 15 pair, lowest somewhat reduced, sessile or nearly so, pairs further apart the closer to the base; pinnules opposite, 3-8 pairs before degenerating into a pinnatifid pinna tip; costae grooved above, grooves continuous from rachis to costae; margins dentate or lobed; veins free, simple or forked, ending before the margin, vein tips usually enlarged to form whitish hydathodes visible above.
Sori: round, in 1 row between midrib and margin, indusium: four lobes encircling sorus, persistent, translucent, basal, surrounding, sporangia: brown then black, maturity: early to midsummer.
Dimensionality: pinnae held nearly horizontally.
Culture Habitat: rock ledges and slopes. Distribution: eastern North America. Hardy to -35C, USDA Zone 3.
Distinctive Characteristics In addition to the genus characteristics, cf.,note the lack of a jointed stipe (a jumble of old stipe bases of various lengths), in summer the diagnostic indusium (see Britton & Brown), in winter the evergreen sterile fronds
Synonyms
Polypodium obtusum Sprengel
Aspidium obtusum Sw.
Cystopteris obtusa Presl
Woodsia perriniana (Sprengel) Hooker & Greville
Woodsia obtusa
Woodsia obtusa. Frond, pinna, sorus of four segments.  Illustration by Edgar Paulton, from How to Know the Ferns and Fern Allies, John T. Mickel, 1979 Wm. C. Brown Co.
Woodsia obtusa
Woodsia obtusa. Habit, early June.  Ray Edwards, 2004.
Woodsia obtusa
Woodsia obtusa. a) fronds, unjointed; b) fertile pinna, glands, scales on the rachis and veins.  Illustration by V. Fulford from Ferns and Fern Allies of Canada, William J. Cody and Donald M. Britton, 1989, Agriculture Canada, used with permission.
Woodsia obtusa
Woodsia obtusa. Vascular bundle an inverted u-shape, the front of the stipe at the bottom of the image.  Drawing from Ferns of Northeastern United States, Farida A. Wiley, 1936.
Woodsia obtusa
Woodsia obtusa sori early summer.  Scan, Tom Stuart
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