Pellaea intermedia |
Pellaea wrightiana |
|
---|---|---|
creeping cliff brake, intermediate cliffbrake |
Wright's cliffbrake |
|
Stems | creeping, horizontal, slender, 2–4 mm diam.; scales mostly bicolored, narrowly lanceolate, largest scales 0.3–0.8 mm wide, centers black, thick, margins brown, thin, irregularly 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. |
Leaves | monomorphic, widely scattered along stem, 12–50 cm; croziers pubescent and bearing a few scales. |
monomorphic, clustered on stem, 6–40 cm; croziers sparsely villous. |
Petiole | straw-colored, tan, or gray, not lustrous, rounded or slightly flattened adaxially, without prominent articulation lines. |
dark brown, lustrous, flattened or slightly grooved adaxially, without prominent articulation lines. |
Blade | ovate to elongate-deltate, usually 2-pinnate proximally, 4–20 cm wide; rachis tan throughout, straight to slightly flexuous, rounded or flattened adaxially, ± pubescent. |
linear-oblong, 2-pinnate proximally, 1.5–5 cm wide; rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous. |
Ultimate segments | ovate to elliptic, 5–15 mm, leathery, glabrous or usually puberulent abaxially; margins recurved on fertile segments, usually covering less than 1/2 abaxial surface, borders whitish, nearly entire; apex obtuse to slightly mucronate. |
narrowly oblong, 5–20 mm, leathery, glabrous; margins recurved on fertile segments, usually covering less than 1/2 abaxial surface, borders whitish, crenulate; apex mucronate. |
Pinnae | perpendicular to rachis or slightly ascending, not decurrent on rachis, usually with 7–21 ultimate segments; costae straight to slightly flexuous, 20–100 mm, longer than ultimate segments. |
perpendicular to rachis or slightly ascending, not decurrent on rachis, usually with 3–9 ultimate segments; costae straight, 2–20 mm, usually shorter than ultimate segments. |
Veins | of ultimate segments obscure. |
of ultimate segments obscure. |
Sporangia | short-stalked, containing 32 spores, not intermixed with farina-producing glands. |
long-stalked, containing 64 spores, intermixed with sparse farina-producing glands. |
n | = 2n = 87, 116, apogamous. |
|
2n | = 116. |
|
Pellaea intermedia |
Pellaea wrightiana |
|
Phenology | Sporulating summer–fall. | Sporulating summer–fall. |
Habitat | Rocky slopes and ledges, on a variety of substrates, including limestone and granite | Cliffs and rocky slopes, on a variety of acidic to mildly basic substrates |
Elevation | 300–2400 m (1000–7900 ft) | 300–2900 m (1000–9500 ft) |
Distribution |
AZ; NM; TX; n Mexico
|
AZ; CO; NC; NM; OK; TX; UT; n Mexico
|
Discussion | Plants of Pellaea intermedia in the flora are apogamous triploids and tetraploids; a sexual diploid cytotype has been found near Saltillo, Mexico (A. F. Tryon 1968). Given the high degree of morphologic similarity among the three cytotypes, the North American polyploids probably were derived from the Mexican diploid through autopolyploidy. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
W. H. Wagner Jr. (1965) suggested that Pellaea wrightiana was a fertile allotetraploid hybrid between P. truncata (as P. longimucronata) and P. ternifolia. This hypothesis has been confirmed by isozyme analyses (M. D. Windham 1988). Pellaea wrightiana is therefore treated as a distinct species rather than a variety of P. ternifolia. This tetraploid species hybridizes with P. truncata and P. ternifolia subsp. arizonica to produce sterile triploids and tetraploids with intermediate morphology and malformed spores. Pellaea wrightiana has also hybridized with P. atropurpurea to form a rare apogamous pentaploid known only from western Oklahoma. (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 | P. intermedia var. pubescens | P. ternifolia var. wrightiana |
Name authority | Mettenius ex Kuhn: Linnaea 38: 84. (1869) | Hooker: Sp. Fil. 2: 142. (1858) |
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