Asplenium montanum
Asplenium pumilum
mountain spleenwort
dwarf spleenwort, hairy spleenwort, triangle spleenwort
proliferous.
proliferous.
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.
erect, unbranched;
scales black with pale margins, linear, extremely narrow, 2–3 mm, only several cells wide.
monomorphic.
monomorphic.
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.
green in small leaves, black abaxially and green adaxially in large leaves, (1–)2–7(–16) cm, 1–2 times length of blade;
indument of fine, nonglandular hairs on veins.
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.
deltate, simple to 2-pinnate, 1–8(–12) × 1–6(–8) cm, thin, papery with scattered hairs on both surfaces;
base truncate;
margins crenate-dentate;
apex pointed, not rooting.
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.
in 0–5 pairs, ovate to deltate, simple to lobed to pinnate proximally, 1–6 × 1–3.5 cm, proximal pinna pair largest;
base broadly cuneate to truncate;
margins irregularly crenate;
apex rounded to pointed.
free, obscure.
free, evident.
1–15 per pinna, on both basiscopic and acroscopic sides.
1–15(–35) per pinna, on both basiscopic and acroscopic sides.
64 per sporangium.
64 per sporangium.
green throughout, dull, sparsely pubescent.
green, dull, glabrous.
= 72.
= 72.
Asplenium montanum
Asplenium pumilum
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.)
Asplenium pumilum is a widespread tropical American fern known only from a few spots in north central Florida. It is a very distinct species, readily recognized by its hairy blades and deltate leaves. Fertile forms vary from simple and only 2 cm to 2-pinnate and 28 cm, and all stages between the two extremes exist. Extreme forms are different enough to suggest that two species might be present.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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