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

adiante du Canada, five-fingered fern, northern maidenhair, northern maidenhair fern

Stems

short-creeping;

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

short-creeping;

scales bronzy deep yellow, concolored, margins entire.

Leaves

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

lax-arching (rarely pendent), closely spaced, 40–75 cm.

Petiole

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

1–2 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.

fan-shaped, pseudopedate, 1-pinnate distally, 15–30 × 15–35 cm, glabrous;

proximal pinnae 3–9-pinnate;

rachis straight, glabrous, occasionally 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.

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.

Indusia

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

transversely oblong, 1–3 mm, glabrous.

Spores

mostly 40–50 µm diam. 2n = 120.

mostly 34–40 µm diam. 2n = 58.

Segment

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

stalks 0.5–1.5(–1.7) mm, dark color entering into segment base.

Adiantum capillus-veneris

Adiantum pedatum

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 Rich, deciduous woodlands, often on humus-covered talus slopes and moist lime soils
Elevation 0–2500 m (0–8200 ft) 0–700 m (0–2300 ft)
Distribution
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
[WildflowerSearch map]
[BONAP county map]
from FNA
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
[WildflowerSearch map]
[BONAP county map]
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.)

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.)

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. tenerum, A. tricholepis, A. viridimontanum
Synonyms A. capillus-veneris var. modestum, A. capillus-veneris var. protrusum, A. capillus-veneris var. rimicola A. pedatum, A. pedatum
Name authority Linnaeus: Sp. Pl. 2: 1096. (1753) Linnaeus: Sp. Pl. 2: 1095. (1753)
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