Argyrochosma jonesii

(Maxon) Windham

Amer. Fern J. 77: 40. 1987.

Illustrated
Basionyms: Notholaena jonesii Maxon Amer. Fern J. 7: 108. 1917
Synonyms: Cheilanthes jonesii (Maxon) Munz Pellaea jonesii (Maxon) C. V. Morton
Treatment appears in FNA Volume 2.

Stem scales brown to nearly black. Leaves 4–15 cm. Petiole dark-brown, 0.75–1.5 mm diam. Blade ovatelanceolate, 2–3-pinnate proximally, leathery, abaxially and adaxially glabrous; rachis rounded to slightly flattened adaxially. Pinna costae straight or nearly so, branches not arising from prominent angles. 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. 2n = 54, 108.


Phenology: Sporulating spring–fall.
Habitat: Calcareous cliffs and ledges
Elevation: 600–1900 m

Distribution

V2 294-distribution-map.gif

Ariz., Calif., Nev., Utah, Mexico in Sonora

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.

Selected References

None.

Lower Taxa

None.

... more about "Argyrochosma jonesii"
Michael D. Windham +
(Maxon) Windham +
cordate +
Notholaena jonesii +
ovatelanceolate +
Ariz. +, Calif. +, Nev. +, Utah +  and Mexico in Sonora +
600–1900 m +
yellow +  and white +
obcordate;reniform +
Calcareous cliffs and ledges +
monomorphic +
recurved +  and reflexed +
noncircinate +  and circinate +
4 cm40 mm <br />0.04 m <br /> (15 cm150 mm <br />0.15 m <br />) +
0.75mm;1.5mm +
flattened +  and rounded +
Sporulating spring–fall. +
nearly +  and straight +
Amer. Fern J. +
flexuous +  and straight +
rounded +  and slightly flattened +
concolored;black;tan;brown +
persistent +
subulate +  and narrowly lanceolate +
Illustrated +
tetrahedral-globose +
dark colored +
erect +  and ascending +
brown +  and nearly black +
Cheilanthes jonesii +  and Pellaea jonesii +
Argyrochosma jonesii +
Argyrochosma +
species +
0 cm0 mm <br />0 m <br /> (?) +  and 0.4 cm4 mm <br />0.004 m <br /> (?) +
crescent--shaped +  and roundish +