Lygodium palmatum (Bernhardi) Swartz

Hartford fern, American climbing fern

Etymology Palmatum means palmately shaped.
Description Rhizome: creeping, branching, stipes 1-4 cm apart, short, blackish or red hairs.
Frond: 300 cm high , evergreen, but the fertile pinnae dying back in winter, monomorphic, blade/stipe ratio: 30:1.
Stipe: twining, branching, shining black, shading to brown and green above, hairy at base, vascular bundles: 1, a simple cylinder.
Blade: 2-pinnate, twining rachis, palmate or pinnate pinnae, transparent hairs on lower surface; a second form in northern areas is glabrous.
Pinnae: alternate, sterile pinnae on 1-2 cm stalks, a pair of pinnules very broadly ovate, deeply and palmately 3-7-lobed, to 6 cm; fertile: contracted, always at the end of the frond, irregularly, palmately 3-6-forked or lobed; costae sometimes ridged or winged; segments sterile: ultimate lobes triangular-elongate to oblong; margins entire; veins free, forking.
Sori: , indusium: false, scale-like, opening along a longitudinal slit, sporangia: in 2 rows, covering the surface of the ultimate segments, maturity: winter, short viability.
Dimensionality: pinnae held horizontally.
Culture Habitat: margins of woods, thickets, and bogs in humus-rich, acid soils, not in shade. Distribution: eastern United States, rare except in Kentucky, Tennessee. Hardy to -35C, USDA Zone 3.
Distinctive Characteristics twining habit, palmate sterile segments
Gisopteris palmata Bernhardi
Ramondia palmata Bosc
Lygodium palmatum
Lygodium palmatum. Frond, sterile and fertile segments.  Illustration by Edgar Paulton, from How to Know the Ferns and Fern Allies, John T. Mickel, 1979 Wm. C. Brown Co.
Spore Maturity Spore collected in the fall fails to germinate, while winter collection is successful -- J. Mickel, personal communication.

Lygodium palmatum. Habit.  Web pages of the Connecticut Botanical Society, with permission.
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