Asplenium monanthes
Asplenium dalhousiae
single-sorus fern, single-sorus spleenwort
Countess dalhousie's spleenwort
not proliferous.
not proliferous.
erect, unbranched;
scales black with lighter margins, linear-lanceolate, 3–6 × 0.4–0.8 mm, margins entire.
erect, unbranched;
scales black with brown margins, lanceolate, 2–5 × 0.6–1 mm, sparsely denticulate.
monomorphic.
monomorphic.
reddish brown throughout, lustrous, 1–12(–20) cm, 1/3–1/10 length of blade;
indument of black filiform scales.
dark to light brown throughout, dull, to 1 cm, 1/10–1/15 length of blade, indument of scales throughout.
linear, 1-pinnate throughout, 5–25(–40) × 1–2.5(–3) cm, thick, glabrous;
base gradually tapered;
apex acute, not rooting.
narrowly elliptic to narrowly lanceolate, pinnatifid, 4–15 × 1.5–6 cm, thick, sparsely puberulent to glabrescent;
base gradually tapered;
apex obtuse, not rooting.
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.
free, obscure.
free, obscure.
1(–3) per pinna, only on basiscopic side.
3–7 pairs per pinna, on both basiscopic and acroscopic sides of lobes.
32 per sporangium.
64 per sporangium.
reddish brown throughout, lustrous, glabrous.
light brown to tan, dull-scaly;
scales brown, lanceolate.
= 2n = 108 (apogamous).
= 72.
Asplenium monanthes
Asplenium dalhousiae
In the flora, Asplenium dalhousiae is found only in the Mule, Huachuca, and Baboquivari mountains of southern Arizona. The pattern of disjunction in the worldwide range of this species is highly unusual.
Asplenium dalhousiae is sometimes placed in the genus Ceterach on the basis of its thick, pinnatifid leaves. Most pteridologists, however, restrict Ceterach to species with densely scaly, pinnatifid leaves. Asplenium dalhousiae is placed in Ceterachopsis by pteridologists who believe it merits its own genus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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