Flora of North America species comparison

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Asplenium adiantum-nigrum

Asplenium

black spleenwort

spleenwort
Roots

not proliferous.

fibrous, not proliferous or proliferous and producing tiny plantlets.
Stems

ascending or short-creeping, infrequently branched;

scales dark brown to blackish throughout, narrowly deltate, 2–4(–5) × 0.2–0.5 mm, margins entire or shallowly denticulate to serrulate.

erect, rarely long-creeping;

scales basally attached, clathrate.
Leaves

monomorphic.

Petiole(s)

dark reddish brown proximally, often fading to green distally, lustrous, 2–20 cm, 2/3–2 times length of blade;

indument of black filiform scales and minute hairs.

not articulate.
Blade(s)

deltate, 2–3-pinnate, 2.5–10 × 2–6.5 cm, thick, hairs dark, scattered, minute;

base truncate;

apex acute to acuminate, not rooting.

1–4-pinnate, of diverse size and shape.
Pinnae

in 4–10 pairs, deltate to lanceolate;

most proximal (largest) pinnae 1.5–4 × 1–2.5 cm;

base obliquely obtuse;

segment margins coarsely incised;

apex acute.

Veins

free, evident.

Indusia

present.
Sori

1–numerous pairs per pinna [1–6 pairs per segment], on both basiscopic and acroscopic sides.

Spores

64 per sporangium.

Rachis

greenish throughout or sometimes reddish brown proximally, lustrous, sparsely pubescent.

x

= 36.
2n

= 144.

Asplenium adiantum-nigrum

Asplenium
Habitat Cliffs
Elevation 1675–2300 m (5500–7500 ft)
Distribution
from FNA
AZ; CO; UT; Eurasia; Africa
[BONAP county map]
from USDA
Worldwide
[BONAP county map]
Discussion

Asplenium adiantum-nigrum is principally a Eurasian species and occurs extremely rarely in North America (see M. G. Shivas 1969 and M. D. Windham 1983 for a discussion of the conspecificity of Western Hemisphere and Eastern Hemisphere material). It is an allotetraploid derived from hybridization of two European taxa, A. cuneifolium Viviani and A. onopteris Linnaeus (M. G. Shivas 1969). Hybrids involving A. adiantum-nigrum and other Asplenium species occur in Europe but are unknown in North America.

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

Species ca. 700 (28 species, 3 nothospecies in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Blades simple, pinnatifid, or forked (sometimes with free pinnae at base), not pinnate throughout.
→ 2
1. Blades pinnate throughout or pinnatifid only in distal 1/3, pinnae undivided to 1–3-divided.
→ 8
2. Blades less than 2–3 mm wide, linear, frequently forking or with 1–3 small, narrow projections.
A. septentrionale
2. Blades more than 10 mm wide, linear-lanceolate to lanceolate, if lobed, segments resembling adnate pinnae.
→ 3
3. Veins anastomosing to form areoles; blades rooting at tip.
A. rhizophyllum
3. Veins free; blades with apical buds or not but not rooting at tip.
→ 4
4. Blades simple, linear to oblanceolate.
→ 5
4. Blades pinnatifid, elliptic, lanceolate, to deltate.
→ 6
5. Blades cordate at base; roots not proliferous.
scolopendrium var. americanum
5. Blades tapered at base; roots proliferous.
A. serratum
6. Petioles 1 cm or less, dull; stem scales 0.6–1 mm wide, sparsely denticulate.
A. dalhousiae
6. Petioles 1–10 cm, lustrous; stem scales less than 0.5 mm wide, entire.
→ 7
7. Petioles dark-pigmented only at base; blade narrowly deltate.
A. pinnatifidum
7. Petioles and proximal midrib darkly pigmented abaxially; blade oblong- lanceolate.
A. ebenoides
8. Blades 2–4-pinnate, with only largest pinnae divided to all pinnae divided.
→ 9
8. Blades 1-pinnate, pinnae undivided (except in some individuals of A. pumilum).
→ 18
9. Blades deltate-ovate, with 2–5 pairs of pinnae; pinnae generally deltate-ovate to obdeltate, rarely lanceolate to narrowly elliptic; color in living plants dull bluish green.
A. ruta-muraria
9. Blades ovate-lanceolate to linear, with 5–20 pairs of pinnae; pinnae linear to oblong; color in living plants shiny green.
→ 10
10. Delicate root proliferations usually present (commonly buried in mossy soil in crevices, but enabling clone formation); damp, shaded limestone; Florida.
→ 11
10. Delicate root proliferations absent or rare; mainly rock crevices; plants not in Florida.
→ 15
11. Spores uniform and normal.
→ 12
11. Spores of different sizes and shapes, malformed (irregular in size and shape).
→ 13
12. Blades oblong-lanceolate, mostly 2- pinnate; pinnae lanceolate to oblong- lanceolate.
A. cristatum
12. Blades narrowly lanceolate, 2–3- pinnate; pinnae ovate to ovate- deltate.
A. verecundum
13. Blades linear-lanceolate, s Florida.
A. ×biscayneanum
13. Blades oblong-lanceolate, c Florida.
→ 14
14. Medial pinnae pinnate throughout; pinnules mostly deeply notched apically.
A. ×curtissii
14. Medial pinnae pinnate only in proximal 1/2; pinnules mostly shallowly notched apically.
A. plenum
15. Buds at blade, pinna, and pinnule apices minute, scaly, dormant; Arizona.
A. exiguum
15. Buds absent; foothills and mountains in e United States and s Rocky Mountains.
→ 16
16. Petioles all pale green except at base.
A. montanum
16. Petioles dark reddish brown.
→ 17
17. Blades lanceolate to linear- lanceolate, 1–2-pinnate; proximal pinnae often somewhat reduced; e United States foothills and mountains.
A. bradleyi
17. Blades deltate-ovate to deltate- lanceolate, 2–3-pinnate; proximal pinnae usually largest; s Rocky Mountains.
A. adiantum-nigrum
18. Pinna pairs 1–2(–4); blades ovate-deltate, with fine nonglandular hairs on veins.
A. pumilum
18. Pinna pairs 5–35; blades mainly oblong to lanceolate, usually with glandular hairs or narrow hairlike scales on veins or blades glabrous.
→ 19
19. Pinnae with conspicuous basal auricles overlapping rachis; sori inframedial; leaves ± dimorphic, upright and tall, or spreading and short; plants often terrestrial.
A. platyneuron
19. Pinnae bases not overlapping rachis; sori medial to supramedial; leaves monomorphic; plants mainly on rock (epiphytic in A. auritum).
→ 20
20. Blades mostly 4–9 cm wide, linear- lanceolate to oblong-lanceolate.
→ 21
20. Blades mostly less than 3 cm wide, mainly linear.
→ 22
21. Blades linear-lanceolate, to 35 cm; pinna pairs 10–22, base with conspicuous acroscopic auricle; epiphytic on tree trunks.
A. auritum
21. Blades oblong to oblong-lanceolate, to 20 cm; pinna pairs 4–8, base with or without small acroscopic auricle; on mossy limestone.
A. abscissum
22. Sori 1(–3), mainly confined to basiscopic side of strongly asymmetric pinnae.
A. monanthes
22. Sori 4–10, on both sides of costa of nearly symmetric pinnae.
→ 23
23. Blade apex prolonged into whiplike extension of rachis terminating in bud.
A. palmeri
23. Blade apex not prolonged, terminal bud absent.
→ 24
24. Pinnae ovate, oblong-ovate, to rhombic, mainly 4–7 mm, length 1–2 times width.
→ 25
24. Pinnae oblong-lanceolate to oblong, mainly 6–10 mm, length 3–5 times width.
→ 28
25. Rachises dark reddish brown throughout.
A. trichomanes
25. Rachises dark in proximal 1/3–2/3 or only at base.
→ 26
26. Rachises dark in proximal 1/3–2/3; pinna margins entire to shallowly crenate.
A. adulterinum
26. Rachises dark only at base; pinna margins dentate-crenate.
→ 27
27. Pinnae with basiscopic 1/2 much reduced; blades mainly less than 1 cm wide; n North America.
A. trichomanes-ramosum
27. Pinnae nearly symmetric; blades mainly more than 1 cm wide; s Florida.
A. trichomanes-dentatum
28. Pinna margins deeply lobed, especially acroscopic and distal margins, cut 1/3 or more distance from margin to costa; s California.
A. vespertinum
28. Pinna margins nearly entire or shallowly crenate- dentate; se United States to e Arizona.
→ 29
29. Pinna margins nearly entire; sori supramedial; spores 32; widespread in s United States.
A. resiliens
29. Pinna margins ± shallowly crenate- dentate; sori medial to inframedial; spores 32 or 64; local in se United States.
→ 30
30. Pinna margins shallowly crenulate; auricle present at pinna base; veins obscure; spores 32 per sporangium.
A. ×heteroresiliens
30. Pinna margins serrate to crenate; auricle rudimentary or absent at pinna base; veins evident; spores 64 per sporangium.
A. heterochroum
Source FNA vol. 2. FNA vol. 2. Authors: Warren H. Wagner Jr., Robbin C. Moran, Charles R. Werth.
Parent taxa Aspleniaceae > Asplenium Aspleniaceae
Sibling taxa
A. abscissum, A. adulterinum, A. auritum, A. bradleyi, A. cristatum, A. dalhousiae, A. ebenoides, A. exiguum, A. heterochroum, A. monanthes, A. montanum, A. palmeri, A. pinnatifidum, A. platyneuron, A. plenum, A. pumilum, A. resiliens, A. rhizophyllum, A. ruta-muraria, A. scolopendrium, A. septentrionale, A. serratum, A. trichomanes, A. trichomanes-dentatum, A. trichomanes-ramosum, A. verecundum, A. vespertinum, A. ×biscayneanum, A. ×curtissii, A. ×heteroresiliens
Subordinate taxa
A. abscissum, A. adiantum-nigrum, A. adulterinum, A. auritum, A. bradleyi, A. cristatum, A. dalhousiae, A. ebenoides, A. exiguum, A. heterochroum, A. monanthes, A. montanum, A. palmeri, A. pinnatifidum, A. platyneuron, A. plenum, A. pumilum, A. resiliens, A. rhizophyllum, A. ruta-muraria, A. scolopendrium var. americanum, A. septentrionale, A. serratum, A. trichomanes, A. trichomanes-dentatum, A. trichomanes-ramosum, A. verecundum, A. vespertinum, A. ×biscayneanum, A. ×curtissii, A. ×heteroresiliens
Synonyms A. andrewsii, A. chihuahuense, A. dubiosum
Name authority Linnaeus: Sp. Pl. 2: 1081. (1753) Linnaeus: Sp. Pl. 2: 1078. 1753; Gen. Pl. ed. 5, 485, (1754)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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