Pellaea atropurpurea
Pellaea mucronata
pelléade à stipe pourpre, purple cliff-brake, purple-stem cliff-brake
bird's-foot fern, birdfoot cliffbrake
compact, ascending, stout, 5–10 mm diam.;
scales uniformly reddish brown (or tan), linear-subulate, 0.1–0.3 mm wide, thin, margins entire to denticulate.
compact, ascending, stout, 5–10 mm diam.;
scales bicolored, linear-subulate, 0.1–0.3 mm wide, centers black, thick, margins brown, thin, erose-dentate.
somewhat dimorphic, sterile leaves shorter and less divided than fertile leaves, clustered on stems, 5–50 cm;
croziers villous.
monomorphic, clustered on stem, 7–45 cm;
croziers sparsely villous.
reddish purple to nearly black, lustrous, rounded adaxially, without prominent articulation lines.
dark brown, lustrous, flattened to slightly grooved adaxially, without prominent articulation lines.
elongate-deltate, usually 2-pinnate proximally, 2–18 cm wide;
rachis reddish purple throughout, straight, rounded adaxially, densely pubescent adaxially with short, curly, appressed hairs.
ovate-deltate, (2–)3-pinnate proximally, 4–18 cm wide;
rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous.
linear-oblong, 10–75 mm, leathery, sparsely villous abaxially near midrib;
margins weakly recurved to plane on fertile segments, usually covering less than 1/2 abaxial surface, borders whitish, crenulate;
apex obtuse to slightly mucronate.
narrowly oblong, 2–12 mm, leathery, glabrous;
margins recurved to strongly revolute on fertile segments, usually covering more than 1/2 abaxial surface, borders greenish, usually dentate;
apex mucronate.
perpendicular to rachis or ascending, not decurrent on rachis, usually with 3–15 ultimate segments;
costae straight, 10–100 mm, often longer than ultimate segments.
perpendicular to rachis to strongly ascending, not decurrent on rachis, usually with 9–40 ultimate segments;
costae straight, 10–70 mm, much longer than ultimate segments.
of ultimate segments obscure.
of ultimate segments obscure.
long-stalked, containing 32 spores, not intermixed with farina-producing glands.
short-stalked, containing 64 spores, intermixed with abundant farina-producing glands.
= 2n = 87, apogamous.
Pellaea atropurpurea
Pellaea mucronata
Contrary to D. B. Lellinger's (1985) hypothesis, isozyme data indicate that neither Pellaea glabella nor P. ternifolia was involved in the origin of this apogamous triploid. Instead, it appears that P. atropurpurea is an autopolyploid derivative of a single diploid taxon that has not yet been located. A thorough survey of spore number per sporangium in this species should be undertaken to determine whether the diploid progenitor is still extant. Collections from western Canada identified as P. atropurpurea actually represent P. gastonyi, an apogamous tetraploid produced by hybridization between P. atropurpurea and diploid populations of P. glabella. Pellaea atropurpurea has also hybridized with P. wrightiana; the hybrid is a rare apogamous pentaploid known only from western Oklahoma. Pellaea lyngholmii is the apogamous tetraploid hybrid between P. atropurpurea and P. truncata. Pellaea atropurpurea is distinguished from all these hybrids by having rachises that are densely pubescent adaxially, larger ultimate segments, and spores averaging less than 62 µm in diameter.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Subspecies 2 (2 in the flora).
Pellaea mucronata encompasses two morphologic extremes that tend to occupy different habitats and are treated here as subspecies. The typical 3-pinnate form (P. mucronata subsp. mucronata) is scattered throughout California and southern Nevada, usually below 1800 m elevation. The 2-pinnate form with ascending, overlapping pinnae (P. mucronata subsp. californica) is apparently confined to the Sierra Nevada and Transverse Ranges of California at elevations greater than 1800 m. The taxonomic status of these entities remains in dispute, and they are often treated as mere ecological forms. W. H. Wagner Jr. et al. (1983) indicated that natural hybrids formed between P. bridgesii and these two taxa are morphologically distinct, suggesting that the differences observed between the subspecies of P. mucronata are genetically based. In addition to P. bridgesii, subsp. mucronata apparently hybridizes with both P. truncata and P. brachyptera (see comments under those species).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Blades 3-pinnate proximally; pinnae usually ± perpendicular to rachis, not overlapping; plants usually found below 1800 m. | subsp. mucronata |
1. Blades usually 2-pinnate proximally; pinnae ascending and overlapping, especially in distal portion of leaf; plants usually found above 1800 m. | subsp. californica |
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