Adiantum pedatum |
Pteridaceae |
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adiante du Canada, five-fingered fern, northern maidenhair, northern maidenhair fern |
brake family, maidenhair fern family |
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Habit | Plants perennial [annual], on rock or terrestrial, of small (rarely large) stature. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | short-creeping; scales bronzy deep yellow, concolored, margins entire. |
compact to creeping, branched or unbranched, dictyostelic, bearing hairs and/or scales. |
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Leaves | lax-arching (rarely pendent), closely spaced, 40–75 cm. |
monomorphic to dimorphic, circinate or noncircinate in bud. |
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Petiole(s) | 1–2 mm diam., glabrous, occasionally glaucous. |
usually with persistent scales proximally, lacking spines; vascular bundles 1–several, roundish or crescent-shaped in cross section. |
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Blade(s) | fan-shaped, pseudopedate, 1-pinnate distally, 15–30 × 15–35 cm, glabrous; proximal pinnae 3–9-pinnate; rachis straight, glabrous, occasionally glaucous. |
1–6-pinnate, without laminar buds. |
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Ultimate segments | oblong, ca. 3 times as long as broad; basiscopic margin straight; acroscopic margin lobed, lobes separated by narrow incisions 0–0.9(–1.1) mm wide; apex obtuse, divided into shallow, rounded lobes separated by shallow sinuses 0.1–2(–3.7) mm deep, margins of lobes crenulate or crenate-denticulate. |
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Veins | pinnate or parallel in ultimate segments of blades, simple or forked, free or infrequently anastomosing in complex patterns. |
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Indusia | transversely oblong, 1–3 mm, glabrous. |
(when present) formed by reflexed, recurved, or revolute leaf margin (false indusium). |
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Sori | borne abaxially on veins, often confluent with age and forming a continuous submarginal band, or sporangia densely covering abaxial surface (acrostichoid); receptacle not or only slightly elevated. |
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Sporangia | stalk of 2–3 rows of cells; annulus vertical, interrupted by stalk; spores 64 or 32 (rarely 16) per sporangium. |
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Spores | mostly 34–40 µm diam. 2n = 58. |
all 1 kind, brown, black, or gray (rarely yellow), globose to globose-tetrahedral or trigonal, occasionally with prominent equatorial ridge, trilete, or trigonal, variously ornamented (usually cristate or rugose). |
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Gametophytes | green, aboveground, obcordate to reniform, sometimes asymmetric, usually glabrous (glandular-farinose in Notholaena); archegonia and antheridia borne on abaxial surface, antheridia 3-celled. |
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Segment | stalks 0.5–1.5(–1.7) mm, dark color entering into segment base. |
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Indument | on petioles, rachises, costae, and blades, rarely absent or commonly of hairs, glands, and/or scales, occasionally of white or yellow farina. |
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Adiantum pedatum |
Pteridaceae |
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Phenology | Sporulating summer–fall. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Rich, deciduous woodlands, often on humus-covered talus slopes and moist lime soils | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 0–700 m (0–2300 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; VA; VT; WI; WV; NB; NS; ON; QC
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Worldwide |
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Discussion | Once considered a single species across its range in North America and eastern Asia, Adiantum pedatum is considered to be a complex of at least three vicariant species (A. pedatum and A. aleuticum occur in North America) and a derivative allopolyploid species (C. A. Paris 1991). Adiantum pedatum in the strict sense is restricted to deciduous woodlands in eastern North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Considerable disagreement exists concerning the circumscription and proper name of this family. The taxa comprising the Pteridaceae in this treatment were assigned to the Sinopteridaceae and Pteridaceae by D. B. Lellinger (1985) and were included in five families by R. E. G. Pichi-Sermolli (1977). The broad concept followed here is similar (except for the exclusion of Ceratopteris) to that espoused by R. M. Tryon and A. F. Tryon (1982), who applied the name Pteridaceae to the group. Until very recently, the newer name Adiantaceae was more commonly used. As represented in North America, Pteridaceae comprise three major evolutionary lines (the adiantoids, the pteroids, and the cheilanthoids). Characteristics holding the family together include abaxial (usually submarginal) sori that lack indusia or are protected by a reflexed or revolute leaf margin, spores that are usually globose-tetrahedral and trilete, and chromosome base numbers of 30 or 29 (rarely 27). The xeric-adapted members of the family (particularly the cheilanthoids) have undergone extensive parallel and convergent evolution, and they have frustrated attempts to produce a natural generic classification based on macromorphologic characteristics alone. Although some workers have aggregated species into a few large genera (e.g., J. T. Mickel 1979b), most tend to recognize smaller segregate genera based on a combination of morphologic, chromosomal, and biochemical data. The latter approach seems to provide a more useful, evolutionarily informative classification and is the one adopted here. Aspidotis and Notholaena are maintained here as distinct from Cheilanthes, and three recently described genera (Argyrochosma, Astrolepis, and Pentagramma) have been incorporated into the treatment. The reasons for these changes in generic circumscription are discussed under the individual genera. Genera ca. 40, species ca. 1000 (13 genera, 90 species in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 2. | FNA vol. 2, p. 122. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Pteridaceae > Adiantum | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | A. pedatum, A. pedatum | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Linnaeus: Sp. Pl. 2: 1095. (1753) | E. D. M. Kirchner | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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