Pellaea ternifolia
Pellaea mucronata
trans-Pecos cliffbrake
bird's-foot fern, birdfoot cliffbrake
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.
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.
monomorphic, clustered on stem, 10–50 cm;
croziers sparsely to densely villous.
monomorphic, clustered on stem, 7–45 cm;
croziers sparsely villous.
black or dark purple, lustrous, rounded or slightly flattened adaxially, without prominent articulation lines.
dark brown, lustrous, flattened to slightly grooved adaxially, without prominent articulation lines.
linear to ovate, deeply pinnate-pinnatifid proximally, 2.5–8 cm wide;
rachis black or purple throughout, straight, often flattened adaxially, glabrous or villous.
ovate-deltate, (2–)3-pinnate proximally, 4–18 cm wide;
rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous.
linear-oblong, 10–40 mm, leathery, glabrous to sparsely villous abaxially on midrib;
margins recurved on fertile segments, rarely covering more than 1/2 abaxial surface, borders whitish, entire;
apex 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 slightly ascending, not decurrent on rachis, ternate at base of leaf;
costae absent.
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 64 spores, not intermixed with farina-producing glands.
short-stalked, containing 64 spores, intermixed with abundant farina-producing glands.
Pellaea ternifolia
Pellaea mucronata
Subspecies 3 (3 in the flora).
Pellaea ternifolia is represented in the flora by three morphologically and chromosomally distinct taxa. These discrete genetic entities also show a tendency toward geographic isolation and are treated here as subspecies. Diploid populations referred to P. ternifolia subsp. ternifolia are scattered from Texas through Mexico to South America. The pubescent tetraploid (P. ternifolia subsp. villosa) follows the Sierra Madre Oriental from Puebla, Mexico, north to Texas; the glabrous tetraploid (P. ternifolia subsp. arizonica) occurs in Arizona, Texas, and northern Mexico. Isozyme and chromosome studies suggest that both tetraploids are segmental allopolyploids produced by hybridization between subsp. ternifolia and other (as yet unidentified) diploid elements within P. ternifolia.
(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. Rachises villous, especially in axils of pinnae; pinnae with hairs scattered along main veins abaxially. | subsp. villosa |
1. Rachises glabrous or with a few widely scattered hairs; pinnae completely glabrous. | → 2 |
2. Largest ultimate segments (excluding terminal pinnae) usually less than 18 mm; distal portion of petioles grooved or flattened adaxially; spores usually 39–45 µm diam. | subsp. ternifolia |
2. Largest ultimate segments (excluding terminal pinnae) usually more than 18 mm; distal portion of petioles rounded or slightly flattened adaxially; spores usually 46–53 µm diam. | subsp. arizonica |
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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