Asplenium monanthes |
Asplenium platyneuron |
|
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single-sorus fern, single-sorus spleenwort |
brownstem spleenwort, doradille ébène, ebony 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, unbranched; scales dark brown to black throughout, narrowly linear-deltate, 2–4 × 0.3–0.6 mm, margins entire. |
Leaves | monomorphic. |
± dimorphic; fertile leaves taller and more erect than sterile leaves. |
Petiole | reddish brown throughout, lustrous, 1–12(–20) cm, 1/3–1/10 length of blade; indument of black filiform scales. |
reddish brown throughout, lustrous, 1–10 cm, 1/4–1/3 length of blade; indument of dark brown to black, filiform scales at base. |
Blade | linear, 1-pinnate throughout, 5–25(–40) × 1–2.5(–3) cm, thick, glabrous; base gradually tapered; apex acute, not rooting. |
lustrous, linear to narrowly oblanceolate, 1-pinnate throughout, 4–50 × 2–5(–7) cm, thin, glabrous, or occasionally sparsely pubescent; base gradually tapered; 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 15–45 pairs, oblong to quadrangular; medial pinnae 1–2.5 × 0.3–0.5 cm; base with conspicuous acroscopic and sometimes basiscopic auricle, this overlapping rachis; margins crenate to serrulate, sometimes more deeply incised in robust specimens; apex acute to obtuse. |
Veins | free, obscure. |
free, evident. |
Sori | 1(–3) per pinna, only on basiscopic side. |
1–12 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 throughout, lustrous, glabrous. |
n | = 2n = 108 (apogamous). |
|
2n | = 72. |
|
Asplenium monanthes |
Asplenium platyneuron |
|
Habitat | Rock | Forest floor or on rocks, often invading masonry and disturbed soils |
Elevation | 50–1000 m (200–3300 ft) | 0–1300 m (0–4300 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
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AL; AR; AZ; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; ON; QC; s Africa
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Discussion | The combining author for Asplenium platyneuron is often given as Oakes ex D. C. Eaton; see D. B. Lellinger (1981) for justification of the authorship employed here. Asplenium platyneuron is remarkable in that it occurs in southern Africa as well as in North America. No other North American fern has this distribution. Asplenium platyneuron is an ecological generalist and is particularly characteristic of disturbed woodlands. This species is migrating northward on the northern portions of its range in the upper Great Lake states (W. H. Wagner Jr. and D. M. Johnson 1981). Proliferous buds on the lowest pinnae allow formation of clumps with stems at several layers in the litter. Asplenium platyneuron hybridizes with A. rhizophyllum, A. trichomanes (producing A. × virginicum Maxon), A. pinnatifidum, A. ruta-muraria (producing A. × morganii W. H. Wagner & F. S. Wagner), A. bradleyi, and A. montanum (producing sterile A. bradleyi). (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 | Acrostichum platyneuron, A. platyneuron var. bacculum-rubrum, A. platyneuron var. incisum | |
Name authority | Linnaeus: Mant. Pl. 1: 130. (1767) | (Linnaeus) Britton: Prelim. Cat. 3. (1888) |
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