Asplenium rhizophyllum
Asplenium pumilum
doradille ambulante, walking fern, walking spleenwort
dwarf spleenwort, hairy spleenwort, triangle spleenwort
not proliferous.
proliferous.
erect or ascending, usually unbranched;
scales dark brown throughout, narrowly deltate, 2–3 × (0.2–)0.5–1 mm, margins entire.
erect, unbranched;
scales black with pale margins, linear, extremely narrow, 2–3 mm, only several cells wide.
monomorphic but fertile leaves generally larger than sterile leaves.
monomorphic.
reddish brown at base, becoming green distally, dull but sometimes lustrous at base, 0.5–12 cm, 0.1–1.5 times length of blade;
indument of dark brown, narrowly deltate scales at base, of minute, club-shaped hairs distally.
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.
highly variable in size and shape, even on 1 plant, narrowly deltate to linear-lanceolate, simple, 1–30 × 0.5–5 cm, leathery, sparsely pubescent, hairs more numerous abaxially than adaxially;
blade base cordate, auriculate, or occasionally hastate, auricles rarely attenuate and radicant;
margins entire to sinuate, rarely irregularly incised;
apex rounded to very long-attenuate and, if attenuate, generally rooting at tip.
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 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.
obscure, anastomosing to form areoles near midrib.
free, evident.
numerous, scattered somewhat irregularly over blade, often joined at vein junctures.
1–15(–35) per pinna, on both basiscopic and acroscopic sides.
64 per sporangium.
64 per sporangium.
green, dull, nearly glabrous.
green, dull, glabrous.
= 72.
= 72.
Asplenium rhizophyllum
Asplenium pumilum
Asplenium rhizophyllum, a diploid species, is morphologically very distinctive within Asplenium and is segregated by many authors, along with its sister species A. ruprechtii Kurata of eastern Asia, into the genus Camptosorus Link. Proliferations arising from leaf tips result in the formation of clonal patches, often dense and extensive, on the mossy boulders and ledges where it typically grows. Naturally occurring sterile hybrids are known with A. platyneuron (these and their fertile allotetraploid derivatives are both referred to A. ebenoides), A. ruta-muraria (A. × inexpectatum E. L. Braun ex C. V. Morton), A. trichomanes subsp. trichomanes [A. × shawneense (R. C. Moran) H. E. Ballard], and A. ebenoides. In addition, the allotetraploid A. pinnatifidum is derived from the hybrid A. montanum × rhizophyllum; the sterile diploid hybrid is unknown.
(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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