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Pellaea atropurpurea

(Purple Cliffbrake)

Overview

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Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in English:

Purple Cliffbrake, Purple-Stem Cliff-Brake, Purple-Stem Cliffbrake

Common Names in French:

Pell, Pelléade à Stipe Pourpre, Pelléade à Stipe Pourpre

Common Names in unspecified:

Purple Cliffbrake, Purple-Stem Cliffbrake

Description

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Family Pteridaceae

Genera ca. 40, species ca. 1000 (13 genera, 90 sp: worldwide.

Considerable disagreement exists concerning the circumscription and proper name of this family . The taxa comprising the Pteridaceae in this treatment were assigned to the Sinopteridaceae and Pteridaceae by D. B . Lellinger (1985) and were included in five families by R. E. G. Pichi-Sermolli (1977). The broad concept followed here is similar (except for the exclusion of Ceratopteris ) to that espoused by R. M. Tryon and A. F. Tryon (1982), who applied the name Pteridaceae to the group. Until very recently, the newer name Adiantaceae was more commonly used.

As represented in North America, Pteridaceae comprise three major evolutionary lines (the adiantoids, the pteroids, and the cheilanthoids). Characteristics holding the family together include abaxial (usually submarginal ) sori that lack indusia or are protected by a reflexed or revolute leaf margin , spores that are usually globose-tetrahedral and trilete, and chromosome base numbers of 30 or 29 (rarely 27). The xeric-adapted members of the family (particularly the cheilanthoids) have undergone extensive parallel and convergent evolution, and they have frustrated attempts to produce a natural generic classification based on macromorphologic characteristics alone. Although some workers have aggregated species into a few large genera (e.g. , J. T. Mickel 1979b), most tend to recognize smaller segregate genera based on a combination of morphologic, chromosomal, and biochemical data. The latter approach seems to provide a more useful, evolutionarily informative classification and is the one adopted here. Aspidotis and Notholaena are maintained here as distinct from Cheilanthes, and three recently described genera ( Argyrochosma, Astrolepis, and Pentagramma ) have been incorporated into the treatment. The reasons for these changes in generic circumscription are discussed under the individual genera.[1]

Genus Pellaea

Plants usually on rock. Stems compact to long-creeping, ascending to horizontal, usually branched; scales brown to tan or often bicolored with dark, central stripe and lighter margins , linear-subulate to lanceolate (rarely ovate ), margins dentate , erose, or entire. Leaves monomorphic to somewhat dimorphic , clustered to widely scattered , 2--100 cm. Petiole brown, black, straw-colored, or gray, rounded , flattened or with single longitudinal groove adaxially, glabrous or pubescent , usually with a few scales at base , with single vascular bundle. Blade linear to ovate-deltate, 1--4-pinnate proximally, leathery or rarely somewhat herbaceous, abaxially glabrous, pubescent, or with hairlike scales scattered along costae, adaxially usually glabrous, dull , not striate ; rachis straight or flexuous . Ultimate segments of blade usually stalked and free from costae, elliptic , lanceolate to linear, usually more than 4 mm wide; base rounded, truncate , or cordate; stalks often lustrous and dark colored ; segment margins reflexed to form confluent , poorly defined, false indusia extending entire length of segment. Veins of ultimate segments free or rarely anastomosing, usually obscure , pinnately branched and divergent distally. False indusia greenish to whitish, narrow, clearly marginal , often concealing the sporangia. Sporangia scattered along veins near segment margins, containing 32 or 64 spores, often intermixed with glands , farina-producing. Spores brown to tan (rarely yellow), tetrahedral-globose, rugose or cristate , lacking prominent equatorial ridge . x = 29.

Species ca. 40 (15 in the flora ) : most in the Western Hemisphere, a small number in Asia, Africa, the Pacific Islands, and Australia.

Pellaea in the broad sense is a diverse , poorly defined assemblage of xeric-adapted ferns (A. R. Smith 1981) . Relationships among the North American, neotropical , and Eastern Hemisphere species are unclear, and it seems likely that the genus, as broadly construed by E. B . Copeland (1947) and R. M. Tryon and A. F. Tryon (1982), is polyphyletic. The species included here in Pellaea belong to a closely knit alliance that is usually recognized as a distinct section (sect. Pellaea ) . Although the inclusion of P . bridgesii in this group has been questioned (A. F. Tryon 1957), W. H. Wagner Jr. et al. (1983) have shown that the aberrant morphology of this species is simply an extreme expression of evolutionary trends commonly encountered in sect. Pellaea .

Among Western Hemisphere cheilanthoid ferns, species of Pellaea show clear morphologic, chromosomal, and biochemical affinities to Argyrochosma and members of the Cheilanthes alabamensis complex . In fact, the glabrous species of Argyrochosma ( A . jonesii and A . microphylla ) are commonly misidentified as Pellaea . These species are easily recognizable, however, because they have a combination of concolored stem scales and small ultimate segments (less than 4 mm wide) .[2]

Physical Description

Species Pellaea atropurpurea

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 . Leaves somewhat dimorphic , sterile leaves shorter and less divided than fertile leaves, clustered on stems, 5--50 cm; croziers villous . Petiole reddish purple to nearly black, lustrous , rounded 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 . 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. 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 . Veins of ultimate segments obscure . Sporangia long-stalked, containing 32 spores, not intermixed with farina-producing glands . n = 2 n = 87, apogamous. Sporulating summer--fall. [source]

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. [source]

Habit: Forb/herb

Flowers: Flower Color: inconspicuous, none

Size/Age/Growth

Size: 6-12" tall.

Habitat

Calcareous cliffs and rocky slopes , usually on limestone; 100--2500 m [3].

Typically found at an altitude of 0 to 4,437 meters (0 to 14,557 feet).[4]

Biology

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Reproduction

Duration: Perennial

Growth

Sunlight: Sun Exposure: Full sun .

Moisture: Drought Tolerance: High

Temperature: Cold Hardiness: 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b. (map)

Taxonomy

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Synonyms

Allosorus atropurpureus (L.) Kunze Ex Presl • Notholaena atropurpurea (L.) Keyserl. • Pellaea atropurpurea var. cristata Trelease • Pellaea × atropurpurea (L.) Link (Pro. Sp.) • Platyloma atropurpurea (L.) J. Sm. • Pteris atropurpurea Linnaeus

Notes

Name Status: Accepted Name .

Last scrutiny: 15-Mar-2000

Similar Species

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Members of the genus Pellaea

ZipcodeZoo has pages for 30 species, subspecies, varieties, forms, and cultivars in this genus:

P. andromedifolia (Coffee Cliffbrake) · P. atropurpurea (Purple Cliffbrake) · P. brachyptera (Sierra Cliff-Brake) · P. breweri (Brewer's Cliff-Brake) · P. bridgesii (Bridges' Cliff-Brake) · P. cordifolia (Heartleaf Cliffbrake) · P. falcata (Australian Cliff Brake) · P. gastonyi (Gastony's Cliffbrake) · P. glabella (Dwarf Cliffbrake) · P. glabella occidentalis (Dwarf Cliffbrake) · P. glabella var. simplex (Dwarf Cliffbrake) · P. glabella subsp. missouriensis (Missouri Cliffbrake) · P. glabella subsp. occidentalis (Western Dwarf Cliffbrake) · P. glabella subsp. simplex (Smooth Cliffbrake) · P. glaciogena (Cliffbrake) · P. intermedia (Intermediate Cliffbrake) · P. lyngholmii (Lyngholm's Cliffbrake) · P. mucronata (Birdfoot Cliffbrake) · P. mucronata subsp. californica (California Cliffbrake) · P. ovata (Cliff Brake Fern) · P. rotundifolia (Button Fern) · P. ternifolia (Cliffbrake) · P. ternifolia subsp. arizonica (Arizonia Cliffbrake) · P. ternifolia subsp. villosa (Transpecos Cliffbrake) · P. truncata (Spiny Cliff-Brake) · P. villosa (Transpecos Cliffbrake) · P. viridis (Green Cliffbrake) · P. viridis var. macrophylla (Green Cliff Brake) · P. wrightiana (Wright Cliff-Brake) · P. x glaciogena (Cliffbrake)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 19, 2007:

Identifiers

Footnotes

  1. Michael D. Windham "Pteridaceae". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  2. Michael D. Windham "Pellaea". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  3. "Pellaea atropurpurea". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  4. Mean = 409.990 meters (1,345.112 feet), Standard Deviation = 421.800 based on 854 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012