Adiantum tenerum

Swartz

Prodr. 135. 1788.

Common names: Brittle maidenhair
Illustrated
Treatment appears in FNA Volume 2.

Stems short-creeping; scales bicolored, centers dark reddish-brown, margins pale tan, erose-ciliate. Leaves arching or sometimes pendent, closely spaced, 20–110 cm. Petiole 1–3 mm diam., glabrous, occasionally glaucous. Blade trowel-shaped, pinnate, 12–60 × 12–60 cm, gradually reduced distally, glabrous; proximal pinnae 3-pinnate; rachis straight, glabrous, not glaucous. Segment stalks 1–5 mm, with dark color ending abruptly at segment base, terminating in cupulelike swelling at base of segment (unlike any other species of Adiantum in the flora). Ultimate segments fan-shaped or rhombic, about as long as broad; base cuneate; apex rounded or acute, lobed, lobes separated by narrow incisions 0.5 mm wide. Indusia transversely oblong to crescent-shaped, 0.5–2 mm, glabrous. Spores mostly 40–58 µm diam. 2n = 60.


Phenology: Sporulating throughout the year.
Habitat: Restricted to moist, shaded, limestone ledges, sink walls, and grottoes in the flora
Elevation: 0–50 m

Distribution

V2 434-distribution-map.gif

Fla., e, s Mexico, Central America in Guatemala, Honduras, Nicaragua, Costa Rica, South America in Venezuela

Discussion

Adiantum tenerum is readily distinguished from other species in the flora by the ultimate segments conspicuously articulate to the stalks.

Selected References

None.

Lower Taxa

None.

"broad" is not a number.

... more about "Adiantum tenerum"
Lobed (?) +, Acute (?) +  and Rounded (?) +
Cathy A. Paris +
Swartz +
cuneate +  and cupulelike +
swelling +
12 cm120 mm <br />0.12 m <br /> (60 cm600 mm <br />0.6 m <br />) +
trowel--shaped +
reduced +
12cm;60cm +
dark reddish-brown +
Brittle maidenhair +
Fla. +, e +, s Mexico +, Central America in Guatemala +, Honduras +, Nicaragua +, Costa Rica +  and South America in Venezuela +
0–50 m +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
yellow +  and white +
obcordate;reniform +
Restricted to moist, shaded, limestone ledges, sink walls, and grottoes in the flora +
transversely oblong +  and crescent-shaped +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
monomorphic +
recurved +  and reflexed +
noncircinate +  and circinate +
20 cm200 mm <br />0.2 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
dentate +, erose-ciliate +  and entire +
chestnut-brown;dark purple or blackish +
glaucous +  and glabrous +
Sporulating throughout the year. +
not glaucous +  and glabrous +
persistent +
linear-lanceolate +  and lanceolate +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Illustrated +
yellowish-brown +  and yellow +
1 +, 32 +  and 64 +
tetrahedral-globose +
suberect +  and long-creeping +
shiny +  and dull +
Adiantum tenerum +
Adiantum +
species +
1 +  and several +
crescent--shaped +  and roundish +
anastomosing +  and simple +
conspicuous +
on rock +  and terrestrial +