Selaginella arizonica

Maxon

Smithsonian Misc. Collect. 72: 5–6. 1920.

Common names: Arizona spike-moss
Illustrated
Treatment appears in FNA Volume 2.

Plants on rock or terrestrial, forming rather loose mats. Stems not readily fragmenting, prostrate, upperside and underside structurally different, irregularly forked, branches determinate, tips upturned in extremely dry conditions. Rhizophores borne on upperside of stem throughout, 0.25–0.3 mm diam. Leaves conspicuously dimorphic, in 8 ranks, tightly appressed to ascending, green; abaxial ridges present; apex with transparent to opaque, flattened bristle 0.1–0.3 mm, sometimes becoming acute (by breaking off of bristle). Underside leaves lanceolate, 2–2.5 × 0.5–0.6 mm; base decurrent, glabrous; margins ciliate, cilia transparent to opaque, spreading or ascending, 0.06–0.13 mm. Upperside leaves linear-lanceolate to slightly falcate (on marginal ranks), 1.9–2.25 × 0.4–0.55 mm; base abruptly adnate, pubescent or glabrous; margins ciliate, cilia transparent to opaque, spreading, 0.06–0.15 mm. Strobili solitary, 5–10 mm; sporophylls ovate-deltate, abaxial ridges not prominent, base glabrous, margins short-ciliate to denticulate, apex acute.


Habitat: In rock crevices or on gravel, on sandstone, igneous, or rarely limestone substrates
Elevation: 600–2000 m

Distribution

V2 485-distribution-map.gif

Ariz., Tex., Mexico in Baja California, Sonora

Discussion

Selaginella arizonica can be further distinguished from the similar S. peruviana by its broad, thin underside leaves. In S. peruviana the underside leaves are narrow and fleshy.

Selected References

None.

Lower Taxa

None.

"thick" is not a number.

... more about "Selaginella arizonica"
transparent +  and opaque +
Iván A. Valdespino +
glabrous +  and pubescent +
decurrent +
acute +  and flattened +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
transparent +  and opaque +
0.006 cm0.06 mm <br />6.0e-5 m <br /> (0.015 cm0.15 mm <br />1.5e-4 m <br />) +
Arizona spike-moss +
Ariz. +, Tex. +, Mexico in Baja California +  and Sonora +
600–2000 m +
In rock crevices or on gravel, on sandstone, igneous, or rarely limestone substrates +
monomorphic +
fertile +  and vegetative +
linear-lanceolate;linear +
ciliate +  and serrate +
short-ciliate;denticulate +
globose +, ovoid +  and tetrahedral +
tetrahedral +
Smithsonian Misc. Collect. +
alternating +
0.025 cm0.25 mm <br />2.5e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
Illustrated +
adjacently +  and monomorphic +
fertile +  and vegetative +
branched +, not +  and articulate +
dimorphic +, climbing +  and cespitose +
decumbent;creeping;prostrate +
quadrangular +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Selaginella arizonica +
Selaginella subg. Tetragonostachys +
species +
branched +  and not articulate +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
erect +  and creeping +
branched +  and not articulate +
0.19 cm1.9 mm <br />0.0019 m <br /> (0.225 cm2.25 mm <br />0.00225 m <br />) +
linear-lanceolate +  and slightly falcate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.055 cm0.55 mm <br />5.5e-4 m <br />) +
erect +  and creeping +
differentiated +
perennial +  and annual +
epiphytic +  and hemiepiphytic +
12 +, 11 +, 10 +, 9 +, 8 +  and 7 +