Pellaea ternifolia |
Pellaea glabella |
|||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
trans-Pecos cliffbrake |
pelléade glabre, simple cliff-brake, slender cliff-brake, smooth cliff-brake, smooth cliffbrake fern |
|||||||||||||||||||||
Stems | 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 uniformly reddish brown, linear-subulate, 0.1–0.3 mm wide, thin, margins sinuous, entire to denticulate. |
||||||||||||||||||||
Leaves | monomorphic, clustered on stem, 10–50 cm; croziers sparsely to densely villous. |
monomorphic, clustered on stem, 2–40 cm; croziers sparsely villous. |
||||||||||||||||||||
Petiole | black or dark purple, lustrous, rounded or slightly flattened adaxially, without prominent articulation lines. |
brown, lustrous, rounded adaxially, occasionally with prominent articulation lines near base. |
||||||||||||||||||||
Blade | linear to ovate, deeply pinnate-pinnatifid proximally, 2.5–8 cm wide; rachis black or purple throughout, straight, often flattened adaxially, glabrous or villous. |
linear-oblong to ovate-lanceolate, 1–2-pinnate proximally, 1–8 cm wide; rachis brown throughout, straight, rounded adaxially, nearly glabrous. |
||||||||||||||||||||
Ultimate segments | 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. |
oblong-lanceolate, 5–20 mm, leathery to herbaceous, glabrous except for occasional hairlike scales abaxially near midrib; margins recurved on fertile segments, covering less than 1/2 abaxial surface, borders whitish, erose-denticulate; apex obtuse. |
||||||||||||||||||||
Pinnae | perpendicular to rachis or slightly ascending, not decurrent on rachis, ternate at base of leaf; costae absent. |
somewhat ascending, decurrent on rachis, usually with 3–7 lobes or ultimate segments; costae when present straight, 1–50 mm, often shorter than ultimate segments. |
||||||||||||||||||||
Veins | of ultimate segments obscure. |
of ultimate segments usually obscure. |
||||||||||||||||||||
Sporangia | long-stalked, containing 64 spores, not intermixed with farina-producing glands. |
long-stalked, containing 32 or 64 spores, not intermixed with farina-producing glands. |
||||||||||||||||||||
Pellaea ternifolia |
Pellaea glabella |
|||||||||||||||||||||
Distribution |
AZ; TX; Mexico; Central America; South America; Pacific Islands in Hawaii
|
AR; AZ; CO; CT; IA; ID; IL; IN; KS; KY; MA; MD; MI; MN; MO; MT; ND; NE; NM; NY; OH; OK; PA; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; ON; QC; SK; only in the flora
|
||||||||||||||||||||
Discussion | 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.) |
Pellaea glabella includes four geographically and genetically isolated taxa treated here as subspecies. D. B. Lellinger (1985) recognized three species in this difficult group, but isozyme analyses (G. J. Gastony 1988) showed that one of these (P. suksdorfiana) is an autotetraploid derivative of the diploid known as P. occidentalis. As a result, Gastony recognized just two species: P. glabella (with two varieties) and P. occidentalis (with two subspecies). The few morphologic features that distinguish these taxa, however, are subtle and environmentally plastic, and the isozyme data indicate that they are less divergent genetically than any other pair of Pellaea species in North America. Therefore, a more conservative taxonomic treatment seems warranted. Subspecies 4. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||||||||||
Key |
|
|
||||||||||||||||||||
Source | FNA vol. 2, p. 180. | FNA vol. 2. | ||||||||||||||||||||
Parent taxa | Pteridaceae > Pellaea | Pteridaceae > Pellaea | ||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||
Synonyms | Pteris ternifolia | |||||||||||||||||||||
Name authority | (Cavanilles) Link: Fil. Spec. 59. (1841) | Mettenius ex Kuhn: Linnaea 36: 87. (1869) | ||||||||||||||||||||
Web links |
|