Argyrochosma jonesii |
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Jones' false cloak-fern, Jones' lipfern |
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Stem | scales brown to nearly black. |
Leaves | 4–15 cm. |
Petiole | dark brown, 0.75–1.5 mm diam. |
Blade | ovate-lanceolate, 2–3-pinnate proximally, leathery, abaxially and adaxially glabrous; rachis rounded to slightly flattened adaxially. |
Ultimate segments | not articulate, dark color of stalks continuing into segment bases abaxially; segment margins plane to slightly recurved, not concealing sporangia; veins obscure adaxially. |
Sporangia | submarginal, borne on distal 1/2 of secondary veins, containing 64 spores. |
Pinna | costae straight or nearly so, branches not arising from prominent angles. |
2n | = 54, 108. |
Argyrochosma jonesii |
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Phenology | Sporulating spring–fall. |
Habitat | Calcareous cliffs and ledges |
Elevation | 600–1900 m (2000–6200 ft) |
Distribution |
AZ; CA; NV; UT; Mexico in Sonora
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Discussion | Argyrochosma jonesii includes two sexually reproducing cytotypes. The diploid is known from a few localities in the Sonoran and Mojave Deserts; the tetraploid is found throughout the Mojave Desert and cismontane southern California. Although subtle morphologic differences exist between these cytotypes, they are distinguished primarily by characteristics known to correlate with increases in ploidy level (such as spore size and the length of stomatal guard cells). Further investigation is necessary to determine whether the tetraploid arose through autopolyploidy or hybridization between cryptic species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. |
Parent taxa | Pteridaceae > Argyrochosma |
Sibling taxa | |
Synonyms | Notholaena jonesii, Cheilanthes jonesii, Pellaea jonesii |
Name authority | (Maxon) Windham: Amer. Fern J. 77: 40. (1987) |
Web links |