Asplenium adiantum-nigrum |
Asplenium abscissum |
|
---|---|---|
black spleenwort |
abscised spleenwort, cutleaf spleenwort |
|
Roots | not proliferous. |
proliferous. |
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, unbranched; scales brown throughout, linear-deltate, 1.2 × 0.1–0.3 mm, margins entire. |
Leaves | monomorphic. |
monomorphic. |
Petiole | 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. |
green throughout, dull, 3–15(–20) cm, 1/3–2/3 length of blade; indument absent. |
Blade | deltate, 2–3-pinnate, 2.5–10 × 2–6.5 cm, thick, hairs dark, scattered, minute; base truncate; apex acute to acuminate, not rooting. |
deltate, 1-pinnate, 7–12(–20) × 3–6(–9) cm, thick, papery, glabrous; base not tapered; apex attenuate, not rooting. |
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. |
in 4–8 pairs, linear-lanceolate; medial pinnae 30–70 × 7–15 mm, slightly curved, strongly excavated in proximal basiscopic 1/3; base with small acroscopic auricle; margins entire to dentate; apex attenuate. |
Veins | free, evident. |
free, obscure. |
Sori | 1–numerous pairs per pinna [1–6 pairs per segment], on both basiscopic and acroscopic sides. |
2–9 pairs, medial, commonly 1–2 less on basiscopic side than on acroscopic side. |
Spores | 64 per sporangium. |
64 per sporangium. |
Rachis | greenish throughout or sometimes reddish brown proximally, lustrous, sparsely pubescent. |
green throughout, dull, glabrous. |
2n | = 144. |
= 72. |
Asplenium adiantum-nigrum |
Asplenium abscissum |
|
Habitat | Cliffs | Shaded limestone boulders, cliff ledges, grottoes, sinkholes |
Elevation | 1675–2300 m (5500–7500 ft) | 0–50 m (0–200 ft) |
Distribution |
AZ; CO; UT; Eurasia; Africa |
FL; Mexico; Central America; West Indies in the Antilles; South America to Bolivia and Brazil |
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.) |
Asplenium abscissum hybridizes with A. verecundum to produce the triploid hybrid, A. × curtissii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. | FNA vol. 2. |
Parent taxa | Aspleniaceae > Asplenium | Aspleniaceae > Asplenium |
Sibling taxa | ||
Synonyms | A. andrewsii, A. chihuahuense, A. dubiosum | |
Name authority | Linnaeus: Sp. Pl. 2: 1081. (1753) | Willdenow: Sp. Pl. 5(1): 321. (1810) |
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