Asplenium monanthes |
Asplenium bradleyi |
|
---|---|---|
single-sorus fern, single-sorus spleenwort |
Bradley's spleenwort |
|
Roots | not proliferous. |
not proliferous. |
Stems | erect, unbranched; scales black with lighter margins, linear-lanceolate, 3–6 × 0.4–0.8 mm, margins entire. |
short-creeping to ascending, occasionally branched; scales dark reddish to brown throughout, narrowly deltate, (2–)3–5 × 0.2–0.4 mm, margins entire or shallowly dentate. |
Leaves | monomorphic. |
monomorphic. |
Petiole | reddish brown throughout, lustrous, 1–12(–20) cm, 1/3–1/10 length of blade; indument of black filiform scales. |
reddish or purplish brown throughout, lustrous, 1–10(–13) cm, 1/3–3/4 length of blade; indument of brown, narrowly lanceolate scales at base, grading into hairs. |
Blade | linear, 1-pinnate throughout, 5–25(–40) × 1–2.5(–3) cm, thick, glabrous; base gradually tapered; apex acute, not rooting. |
narrowly oblong to lanceolate, pinnate-pinnatifid to 2-pinnate, 2–17(–20) × 1–6 cm, thin to moderately thick, sparsely pubescent; base truncate or obtuse; apex acute, not rooting. |
Pinnae | in 10–40 pairs, oblong to quadrangular, somewhat asymmetric; medial pinnae 4–15 × 2–5 mm; base rounded to cuneate; margins crenulate or ± entire; apex obtuse. |
in (3–)5–15(–25) pairs, ovate, obovate to lanceolate or deltate-lanceolate; medial pinnae 6–40 × 3–10 mm; base truncate to obliquely obtuse; margins dentate to denticulate; apex acute or rounded. |
Veins | free, obscure. |
free, barely evident. |
Sori | 1(–3) per pinna, only on basiscopic side. |
3 to numerous pairs per pinna, on both basiscopic and acroscopic sides. |
Spores | 32 per sporangium. |
64 per sporangium. |
Rachis | reddish brown throughout, lustrous, glabrous. |
reddish or purplish brown proximally, fading to green in distal 1/3–2/3, lustrous, sparsely pubescent. |
n | = 2n = 108 (apogamous). |
|
2n | = 144. |
|
Asplenium monanthes |
Asplenium bradleyi |
|
Habitat | Rock | Acidic rocks, usually on steep ledges |
Elevation | 50–1000 m (200–3300 ft) | 0–1000 m (0–3300 ft) |
Distribution |
AL; AZ; NC; SC; HI; Mexico; Central America; West Indies in Hispaniola; Jamaica; South America to n Argentina; Africa including Madagascar; Madeira; Réunion; Tristan da Cunha
|
AL; AR; GA; IL; KY; MD; MO; NC; NJ; NY; OH; OK; PA; SC; TN; VA; WV
|
Discussion | Asplenium bradleyi is a morphologically variable species, the allotetraploid derivative of A. montanum × platyneuron (W. H. Wagner Jr. 1954; D. M. Smith and D. A. Levin 1963; C. R. Werth et al. 1985). The sterile diploid form of A. bradleyi has been collected twice in nature (W. H. Wagner Jr. et al. 1973; A. M. Evans 1988), and isozyme studies indicate that the allotetraploid has had a polytopic origin (C. R. Werth et al. 1985b). Occurring rarely to locally in the Appalachian region, A. bradleyi overlaps with both progenitor taxa, but it is fairly frequent in the Ozark and Ouachita region where A. montanum is absent. Sterile hybrids with A. pinnatifidum (A. × gravesii), A. montanum (A. × wherryi D. M. Smith et al.), and A. platyneuron are known from nature. (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. stotleri | |
Name authority | Linnaeus: Mant. Pl. 1: 130. (1767) | D. C. Eaton: Bull. Torrey Bot. Club 4: 11. (1873) |
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