Pellaea atropurpurea |
Pellaea brachyptera |
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pelléade à stipe pourpre, purple cliff-brake, purple-stem cliff-brake |
Sierra cliff-brake, Sierran cliffbrake |
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Stems | 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 dark brown to black, thick, margins brown, thin, dentate. |
Leaves | somewhat dimorphic, sterile leaves shorter and less divided than fertile leaves, clustered on stems, 5–50 cm; croziers villous. |
monomorphic, clustered on stem, 8–40 cm; croziers sparsely villous. |
Petiole | reddish purple to nearly black, lustrous, rounded adaxially, without prominent articulation lines. |
dark brown, lustrous, flattened or slightly grooved adaxially, without prominent articulation lines. |
Blade | 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. |
linear-oblong, 2-pinnate proximally, 1–4 cm wide; rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous. |
Ultimate segments | 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. |
linear, 5–20 mm, leathery, glabrous; margins on fertile segments strongly revolute, covering more than 1/2 abaxial surface, borders greenish, crenate; apex mucronate. |
Pinnae | 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. |
strongly ascending, not decurrent on rachis, usually with 5–11 ultimate segments; costae straight, 5–20 mm, usually shorter than ultimate segments. |
Veins | of ultimate segments obscure. |
of ultimate segments obscure. |
Sporangia | long-stalked, containing 32 spores, not intermixed with farina-producing glands. |
short-stalked, containing 64 spores, intermixed with abundant farina-producing glands. |
n | = 2n = 87, apogamous. |
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Pellaea atropurpurea |
Pellaea brachyptera |
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Phenology | Sporulating summer–fall. | Sporulating summer–fall. |
Habitat | Calcareous cliffs and rocky slopes, usually on limestone | Cliffs and rocky slopes, usually on igneous substrates, occasionally on serpentine |
Elevation | 100–2500 m (300–8200 ft) | 900–2700 m (3000–8900 ft) |
Distribution |
AL; AR; AZ; CO; CT; DC; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NM; NV; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; VT; WI; WV; WY; ON; QC; Mexico; Central America in Guatemala
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CA; OR; WA
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Discussion | 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.) |
The distinctive Pellaea brachyptera reportedly hybridizes with P. mucronata (A. F. Tryon 1957; D. B. Lellinger 1985); the hybrids are morphologically intermediate plants with malformed spores. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. | FNA vol. 2. |
Parent taxa | Pteridaceae > Pellaea | Pteridaceae > Pellaea |
Sibling taxa | ||
Synonyms | Pteris atropurpurea, P. atropurpurea var. cristata | Platyloma brachyptera |
Name authority | (Linnaeus) Link: Fil. Spec. 59. (1841) | (T. Moore) Baker: in Hooker & Baker, Syn. Fil. ed. 2 477. (1874) |
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