Asplenium adiantum-nigrum
Asplenium montanum
black spleenwort
mountain spleenwort
not proliferous.
proliferous.
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.
horizontal, often arching upward, unbranched (although clusters of stems often form from root proliferations, giving false appearance of single much-branched stem);
scales dark brown throughout, narrowly deltate, 2–4 × 0.2–0.4 mm, margins entire.
monomorphic.
monomorphic.
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.
dark brown to purplish black, lustrous proximally, fading to green distally, 2–11 cm, 1/2–1 1/2 length of blade;
indument of blackish, narrowly lanceolate scales only at very base and of minute hairs.
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 to lanceolate, 1–2-pinnate-pinnatifid, 2–11 × 1–7(–10) cm, thick, essentially glabrous;
base truncate or obtuse;
apex acuminate to acute, not rooting.
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 4–10 pairs, deltate to lanceolate;
proximal (longest) pinnae 6–35 × 4–20 mm;
base obtuse to acute;
margins coarsely incised;
apex acute to rounded.
free, evident.
free, obscure.
1–numerous pairs per pinna [1–6 pairs per segment], on both basiscopic and acroscopic sides.
1–15 per pinna, on both basiscopic and acroscopic sides.
64 per sporangium.
64 per sporangium.
greenish throughout or sometimes reddish brown proximally, lustrous, sparsely pubescent.
green throughout, dull, sparsely pubescent.
= 144.
= 72.
Asplenium adiantum-nigrum
Asplenium montanum
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 montanum occurs principally in the Appalachian region, with outlying localities in the Shawnee Hills of western Kentucky (R. Cranfill 1980) and adjacent Indiana (D. M. Smith 1956). A report of its disjunct occurrence on the northern edge of the Ozarks is based on a single specimen whose label indicates the collection locality near Graham Cave, Montgomery County, Missouri. Efforts by several botanists to relocate the population have failed. Reports of a disjunct station in the upper peninsula of Michigan are doubtful.
Asplenium montanum is an ecological specialist. It is typically the sole vascular plant species in the siliceous rock crevices in which it is found. It may occur, however, with two allotetraploid species, A. bradleyi and A. pinnatifidum, which were derived from hybrids of A. montanum with A. platyneuron and A. rhizophyllum, respectively. In addition, A. montanum crosses frequently with A. pinnatifidum producing A. × trudellii and rarely with allotetraploid individuals of A. bradleyi producing A. × wherryi.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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