Cheilanthes eatonii |
Pteridaceae |
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Eaton's lip fern |
brake family, maidenhair fern family |
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Habit | Plants perennial [annual], on rock or terrestrial, of small (rarely large) stature. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | compact, 4–8 mm diam.; scales mostly bicolored, with broad, well-defined, dark, central stripe and narrow, light brown margins, linear-lanceolate, straight to slightly contorted, loosely appressed, persistent. |
compact to creeping, branched or unbranched, dictyostelic, bearing hairs and/or scales. |
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Leaves | clustered, 6–35 cm; vernation noncircinate. |
monomorphic to dimorphic, circinate or noncircinate in bud. |
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Petiole(s) | dark brown, rounded adaxially. |
usually with persistent scales proximally, lacking spines; vascular bundles 1–several, roundish or crescent-shaped in cross section. |
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Blade(s) | oblong-lanceolate, 3–4-pinnate at base, 1.5–5 cm wide; rachis rounded adaxially, with scattered linear-lanceolate scales and monomorphic pubescence. |
1–6-pinnate, without laminar buds. |
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Ultimate segments | oval to round, beadlike, the largest 1–3 mm, abaxially densely tomentose, adaxially pubescent with fine, unbranched hairs or glabrescent. |
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Pinnae | not articulate, dark color of stalk continuing into pinna base, basal pair not conspicuously larger than adjacent pair, usually equilateral, appearing tomentose to glabrescent adaxially. |
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Veins | pinnate or parallel in ultimate segments of blades, simple or forked, free or infrequently anastomosing in complex patterns. |
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Indusia | (when present) formed by reflexed, recurved, or revolute leaf margin (false indusium). |
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False indusia | marginal to obscurely inframarginal, somewhat differentiated, 0.05–0.25 mm wide. |
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Sori | ± continuous around segment margins. |
borne abaxially on veins, often confluent with age and forming a continuous submarginal band, or sporangia densely covering abaxial surface (acrostichoid); receptacle not or only slightly elevated. |
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Sporangia | containing 32 spores. |
stalk of 2–3 rows of cells; annulus vertical, interrupted by stalk; spores 64 or 32 (rarely 16) per sporangium. |
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Spores | all 1 kind, brown, black, or gray (rarely yellow), globose to globose-tetrahedral or trigonal, occasionally with prominent equatorial ridge, trilete, or trigonal, variously ornamented (usually cristate or rugose). |
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Gametophytes | green, aboveground, obcordate to reniform, sometimes asymmetric, usually glabrous (glandular-farinose in Notholaena); archegonia and antheridia borne on abaxial surface, antheridia 3-celled. |
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Costae | green adaxially for most of length; abaxial scales multiseriate, lanceolate to linear, truncate or subcordate at base, without overlapping basal lobes, conspicuous, the largest 0.4–0.7 mm wide, loosely imbricate, not concealing ultimate segments, erose-dentate, rarely with 1–2 cilia at base on a few scales. |
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n | = 2n = 90, 120, apogamous. |
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Indument | on petioles, rachises, costae, and blades, rarely absent or commonly of hairs, glands, and/or scales, occasionally of white or yellow farina. |
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Cheilanthes eatonii |
Pteridaceae |
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Phenology | Sporulating summer–fall. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Rocky slopes and ledges, found on a variety of substrates including limestone and granite | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 300–3000 m (1000–9800 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AR; AZ; CO; NM; OK; TX; UT; VA; WV; Mexico; Central America in Costa Rica |
Worldwide |
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Discussion | As here circumscribed, Cheilanthes eatonii is a variable species comprising apogamous triploid and tetraploid cytotypes of unknown parentage. It includes plants previously identified as C. castanea and C. pinkavii (ined.). Type specimens of C. eatonii and C. castanea are quite distinct morphologically, but most plants here included within C. eatonii are intermediate between these two extremes (T. Reeves 1979). Because there is no clear morphologic break, C. castanea is placed here in synonymy under C. eatonii pending further study. Reports of hybridization between C. eatonii and C. villosa (D. B. Lellinger 1985) are based on specimens from western Texas and southern New Mexico that appear to be intermediate between these taxa in several characters. T. Reeves (1979) applied the name C. pinkavii to these specimens; that name has never been validly published. Formal recognition of this taxon is deferred pending completion of a biosystematic study of the C. eatonii complex as a whole. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. Genera ca. 40, species ca. 1000 (13 genera, 90 species in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 2. | FNA vol. 2, p. 122. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Pteridaceae > Cheilanthes | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | C. castanea, C. eatonii | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Baker: in Hooker & Baker, Syn. Fil. 4: 140. (1867) | E. D. M. Kirchner | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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