Asplenium rhizophyllum Linnaeus

Walking fern

Etymology Rhizophyllum means with rooting leaves.
Description Rhizome: erect, short, scales clathrate, dark brown, narrowly deltate, to 3mm.
Frond: 30 cm high by 5 cm wide, evergreen, monomorphic but fertile leaves generally larger than sterile leaves, blade/stipe ratio: 1:1 to 9:1 or blade shorter than stipe.
Stipe: reddish brown at base, becoming green, dark brown, narrowly deltate scales at base,minute, club-shaped hairs above, vascular bundles: 2 C-shaped, back to back, uniting to 1 upwards to an X-shape.
Blade: simple, narrowly deltate to linear-lanceolate, variable in size and shape, basal lobes usually rounded, but sometimes pointed, even on 1 plant, apex rounded to very long-tapering and, if tapering, generally rooting at tip, leathery, sparsely hairy, hairs more numerous below than above.
Pinnae: none; costae rachis green, dull, nearly glabrous, grooved above; margins entire to sinuate, rarely irregularly incised; veins obscure, netting near the midrib.
Sori: linear, but following the veins, scattered somewhat irregularly over blade, often joined at vein junction, indusium: green, shriveling, inconspicuous, along the vein, sporangia: golden yellow young, reddish-brown later, maturity: midsummer to early fall.
Culture Habitat: shady, mossy limestone rocks, occasionally sandstone substrates. Distribution: eastern North America. Hardy to -35C, USDA Zone 3.
Distinctive Characteristics There are few temperate ferns with simple fronds and fewer still developing new plants at frond apex. Yes, there is Camptosoros sibiricus, a smaller plant, not listed here, whose fronds are widest well above a constricted base vs. widest at the base here.
Synonyms
Camptosorus rhizophyllus (Linnaeus) Link
Asplenium rhizophyllum
Asplenium rhizophyllum. a) simple fronds, one tip rooting; b) portion of fertile frond.  Illustration by V. Fulford from Ferns and Fern Allies of Canada, William J. Cody and Donald M. Britton, 1989, Agriculture Canada, used with permission.
Notes
Taxonomy This species is also placed in the genus Camptosorus, perhaps largely because of net-veining near the rachis, but its ability to hybridize with other members of Asplenium is regarded as outweighing separation.
Asplenium rhizophyllum
Asplenium rhizophyllum. Two c-shaped vascular bundles, back to back, at the base of the stipe.  Drawing from Ferns of Northeastern United States, Farida A. Wiley, 1936.
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