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black maidenhair fern, common maidenhair, southern maiden-hair, southern maidenhair fern, Venus hair, Venus hair fern, Venus's-hair fern

Green Mountain maidenhair, Green Mountain maidenhair fern



scales golden brown to medium brown, concolored, iridescent, margins entire or occasionally with single broad tooth near base.


scales bronzy deep yellow, concolored, margins entire.


lax-arching or pendent, closely spaced, 15–75 cm.

arching to stiffly erect, often densely clustered, 38–75(–90) cm.


0.5–1.5 mm diam., glabrous, occasionally glaucous.

1–3 mm diam., glabrous, often glaucous.


lanceolate, pinnate, 10–45 × 4–15 cm, glabrous, gradually reduced distally;

proximal pinnae 3(–4)-pinnate;

rachis straight to flexuous, glabrous, not glaucous.

fan-shaped to funnel-shaped, pseudopedate, 1-pinnate distally, 10–35 × 10–35(–45) cm, glabrous;

proximal pinnae 2–7-pinnate;

rachis straight, glabrous, often 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.

long-triangular, ca. 2.5 times as long as broad;

basiscopic margin oblique;

acroscopic margin lobed, lobes separated by narrow (less than 1 mm) incisions;

apex acute, usually entire.


transversely oblong or crescent-shaped, 1–3(–7) mm, glabrous.

False indusia

transversely oblong, mostly 2–5(–10) mm, glabrous.


mostly 40–50 µm diam. 2n = 120.

mostly 45–58 µm diam. 2n = 116.


stalks 0.5–3.5 mm, dark color extending into segment base.

stalks (0.4–)0.6–1.5(–1.9) mm, dark color commonly entering into segment base.

Adiantum capillus-veneris

Adiantum viridimontanum

Phenology Sporulating spring–summer. Sporulating summer–fall.
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 Restricted to serpentine sites where it occurs in rock clefts, on talus slopes, and in well-developed serpentine soils
Elevation 0–2500 m (0–8200 ft) 200–800 m (700–2600 ft)
from FNA
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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[BONAP county map]
from FNA
[BONAP county map]

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.)

Adiantum viridimontanum, an allopolyploid from a sterile hybrid between A. pedatum and A. aleuticum, is known only from north central Vermont (C. A. Paris and M. D. Windham 1988). Additional populations may eventually be located on serpentine in southern Quebec.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 2. FNA vol. 2.
Parent taxa Pteridaceae > Adiantum Pteridaceae > Adiantum
Sibling taxa
A. aleuticum, A. hispidulum, A. jordanii, A. melanoleucum, A. pedatum, A. tenerum, A. tricholepis, A. viridimontanum
A. aleuticum, A. capillus-veneris, A. hispidulum, A. jordanii, A. melanoleucum, A. pedatum, A. tenerum, A. tricholepis
Synonyms A. capillus-veneris var. modestum, A. capillus-veneris var. protrusum, A. capillus-veneris var. rimicola
Name authority Linnaeus: Sp. Pl. 2: 1096. (1753) Paris: Rhodora 93: 108. (1991)
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