Selaginella arenicola subsp. riddellii

(Van Eseltine) R. M. Tryon

Ann. Missouri Bot. Gard. 42: 24. 1955.

Common names: Riddell's spike-moss
Endemic
Basionyms: Selaginella riddellii Contr. U.S. Natl. Herb. 20: 162. 1918
Treatment appears in FNA Volume 2.

Leaves (aerial stems) usually loosely appressed; base often glabrescent. Strobili sometimes with apical vegetative growth, not distinctly larger than subtending stem. Sporophylls usually not abruptly tapering toward apex; apex straight.


Habitat: Mostly on granite outcrops, granite boulders, or gravelly or sandy soil
Elevation: 0–200 m

Distribution

V2 355-distribution-map.gif

Ala., Ark., Ga., La., Okla., Tex.

Discussion

The specimens of Selaginella arenicola subsp. riddellii from Texas are more constant in their morphologic characteristics and thus more easily separated from subsp. arenicola.

Selected References

None.

Lower Taxa

None.

"thick" is not a number.

straight +
Bristled (?) +, Attenuate (?) +  and Plane (?) +
Iván A. Valdespino +
(Van Eseltine) R. M. Tryon +
glabrescent +
decurrent +  and cuneate +
Selaginella riddellii +
0.085 cm0.85 mm <br />8.5e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
white;whitish +
0.025 cm0.25 mm <br />2.5e-4 m <br /> (0.085 cm0.85 mm <br />8.5e-4 m <br />) +
transparent +
dentiform +
0.002 cm0.02 mm <br />2.0e-5 m <br /> (0.007 cm0.07 mm <br />7.0e-5 m <br />) +
Riddell's spike-moss +
Ala. +, Ark. +, Ga. +, La. +, Okla. +  and Tex. +
0–200 m +
Mostly on granite outcrops, granite boulders, or gravelly or sandy soil +
monomorphic +
fertile +  and vegetative +
linear-lanceolate;linear +
ciliate +  and serrate +
ciliate +  and short-ciliate +
globose +, ovoid +  and tetrahedral +
tetrahedral +
Ann. Missouri Bot. Gard. +
alternating +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.033 cm0.33 mm <br />3.3e-4 m <br />) +
adjacently +  and monomorphic +
fertile +  and vegetative +
lanceolate +, triangular-lanceolate +  and scale-like +
0.4mm;0.5mm +
rhizomatous +
budlike +  and symmetric +
dimorphic +, climbing +  and cespitose +
decumbent;creeping;prostrate +
aerial +  and underground +
ascending;erect;ascending +
3 cm30 mm <br />0.03 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
quadrangular +
not distinctly larger +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Selaginella arenicola subsp. riddellii +
Selaginella arenicola +
subspecies +
straight +
branched +  and not articulate +
erect +  and creeping +
branched +  and not articulate +
erect +  and creeping +
differentiated +
perennial +  and annual +
on rock +  and terrestrial +
epiphytic +  and hemiepiphytic +
12 +, 11 +, 10 +, 9 +, 8 +  and 7 +