Adiantum capillus-veneris |
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black maidenhair fern, common maidenhair, southern maiden-hair, southern maidenhair fern, Venus hair, Venus hair fern, Venus's-hair fern |
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Stems | short-creeping; scales golden brown to medium brown, concolored, iridescent, margins entire or occasionally with single broad tooth near base. |
Leaves | lax-arching or pendent, closely spaced, 15–75 cm. |
Petiole | 0.5–1.5 mm diam., glabrous, occasionally glaucous. |
Blade | lanceolate, pinnate, 10–45 × 4–15 cm, glabrous, gradually reduced distally; proximal pinnae 3(–4)-pinnate; rachis straight to flexuous, glabrous, not glaucous. |
Ultimate segments | various, generally cuneate or fan-shaped to irregularly rhombic (plants in American southwest occasionally with segments nearly round), about as long as broad; base broadly to narrowly cuneate; margins shallowly to deeply lobed, incisions 0.5–7 mm, occasionally ± laciniate, sharply denticulate in sterile segments; apex rounded to acute. |
Indusia | transversely oblong or crescent-shaped, 1–3(–7) mm, glabrous. |
Spores | mostly 40–50 µm diam. 2n = 120. |
Segment | stalks 0.5–3.5 mm, dark color extending into segment base. |
Adiantum capillus-veneris |
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Phenology | Sporulating spring–summer. |
Habitat | Moist calcareous cliffs, banks, and ledges along streams and rivers, walls of lime sinks, canyon walls (in the American southwest), around foundations, on mortar of storm drains |
Elevation | 0–2500 m [0–8200 ft] |
Distribution |
AL; AR; AZ; CA; CO; FL; GA; KY; LA; MO; MS; NC; NM; NV; OK; SC; SD; TN; TX; UT; VA; BC; Mexico; Central America; West Indies; South America in Venezuela; Peru; tropical to warm temperate regions in Eurasia and Africa
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Discussion | No evident pattern to morphologic variation in the species is discernible, although a number of segregate species and infraspecific taxa have been recognized within North American Adiantum capillus-veneris. In the Eastern Hemisphere, the species is diploid, with 2n = 60 (I. Manton 1950). Several tetraploid counts have been reported from North America (W. H. Wagner Jr. 1963). Spore-measurement data suggest, however, that the polyploid cytotype may not be widely distributed. Further investigation is needed to determine whether Adiantum capillus-veneris populations in North America are conspecific with those in Eurasia and Africa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. |
Parent taxa | |
Sibling taxa | |
Synonyms | A. capillus-veneris var. modestum, A. capillus-veneris var. protrusum, A. capillus-veneris var. rimicola |
Name authority | Linnaeus: Sp. Pl. 2: 1096. (1753) |
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